diff --git a/CHANGELOG.md b/CHANGELOG.md
index 84784c22f8..9256b7e3bd 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,9 +1,11 @@
-## 0.15.14-dev3
+## 0.15.14-dev4
 
 ### Enhancements
 
 ### Features
 
+* **Add (but do not install) a new post-partitioning decorator to handle metadata added for all file-types, like `.filename`, `.filetype` and `.languages`.** This will be installed in a closely following PR to replace the four currently being used for this purpose.
+
 ### Fixes
 
 * **Update Python SDK usage in `partition_via_api`.** Make a minor syntax change to ensure forward compatibility with the upcoming 0.26.0 Python SDK.
diff --git a/test_unstructured/partition/test_lang.py b/test_unstructured/partition/common/test_lang.py
similarity index 85%
rename from test_unstructured/partition/test_lang.py
rename to test_unstructured/partition/common/test_lang.py
index f1d743a8b8..076b405a71 100644
--- a/test_unstructured/partition/test_lang.py
+++ b/test_unstructured/partition/common/test_lang.py
@@ -6,15 +6,15 @@
 
 import os
 import pathlib
-from typing import Union
 
 import pytest
 
+from test_unstructured.unit_utils import LogCaptureFixture
 from unstructured.documents.elements import (
     NarrativeText,
     PageBreak,
 )
-from unstructured.partition.lang import (
+from unstructured.partition.common.lang import (
     _clean_ocr_languages_arg,
     _convert_language_code_to_pytesseract_lang_code,
     apply_lang_metadata,
@@ -61,13 +61,13 @@ def test_prepare_languages_for_tesseract_with_multiple_languages():
     assert prepare_languages_for_tesseract(languages) == "jpn+jpn_vert+afr+eng+equ"
 
 
-def test_prepare_languages_for_tesseract_warns_nonstandard_language(caplog):
+def test_prepare_languages_for_tesseract_warns_nonstandard_language(caplog: LogCaptureFixture):
     languages = ["zzz", "chi"]
     assert prepare_languages_for_tesseract(languages) == "chi_sim+chi_sim_vert+chi_tra+chi_tra_vert"
     assert "not a valid standard language code" in caplog.text
 
 
-def test_prepare_languages_for_tesseract_warns_non_tesseract_language(caplog):
+def test_prepare_languages_for_tesseract_warns_non_tesseract_language(caplog: LogCaptureFixture):
     languages = ["kbd", "eng"]
     assert prepare_languages_for_tesseract(languages) == "eng"
     assert "not a language supported by Tesseract" in caplog.text
@@ -79,7 +79,7 @@ def test_prepare_languages_for_tesseract_None_languages():
         prepare_languages_for_tesseract(languages)
 
 
-def test_prepare_languages_for_tesseract_no_valid_languages(caplog):
+def test_prepare_languages_for_tesseract_no_valid_languages(caplog: LogCaptureFixture):
     languages = [""]
     assert prepare_languages_for_tesseract(languages) == "eng"
     assert "Failed to find any valid standard language code from languages" in caplog.text
@@ -96,11 +96,11 @@ def test_prepare_languages_for_tesseract_no_valid_languages(caplog):
         ("kor", "korean"),
     ],
 )
-def test_tesseract_to_paddle_language_valid_codes(tesseract_lang, expected_lang):
+def test_tesseract_to_paddle_language_valid_codes(tesseract_lang: str, expected_lang: str):
     assert expected_lang == tesseract_to_paddle_language(tesseract_lang)
 
 
-def test_tesseract_to_paddle_language_invalid_codes(caplog):
+def test_tesseract_to_paddle_language_invalid_codes(caplog: LogCaptureFixture):
     tesseract_lang = "unsupported_lang"
     assert tesseract_to_paddle_language(tesseract_lang) == "en"
     assert "unsupported_lang is not a language code supported by PaddleOCR," in caplog.text
@@ -114,7 +114,7 @@ def test_tesseract_to_paddle_language_invalid_codes(caplog):
         ("DEU", "german"),
     ],
 )
-def test_tesseract_to_paddle_language_case_sensitivity(tesseract_lang, expected_lang):
+def test_tesseract_to_paddle_language_case_sensitivity(tesseract_lang: str, expected_lang: str):
     assert expected_lang == tesseract_to_paddle_language(tesseract_lang)
 
 
@@ -139,7 +139,7 @@ def test_detect_languages_gets_multiple_languages():
     assert detect_languages(text) == ["ces", "pol", "slk"]
 
 
-def test_detect_languages_warns_for_auto_and_other_input(caplog):
+def test_detect_languages_warns_for_auto_and_other_input(caplog: LogCaptureFixture):
     text = "This is another short sentence."
     languages = ["en", "auto", "rus"]
     assert detect_languages(text, languages) == ["eng"]
@@ -149,10 +149,10 @@ def test_detect_languages_warns_for_auto_and_other_input(caplog):
 def test_detect_languages_raises_TypeError_for_invalid_languages():
     with pytest.raises(TypeError):
         text = "This is a short sentence."
-        detect_languages(text, languages="eng") == ["eng"]
+        detect_languages(text, languages="eng") == ["eng"]  # type: ignore
 
 
-def test_apply_lang_metadata_has_no_warning_for_PageBreak(caplog):
+def test_apply_lang_metadata_has_no_warning_for_PageBreak(caplog: LogCaptureFixture):
     elements = [NarrativeText("Sample text."), PageBreak("")]
     elements = list(
         apply_lang_metadata(
@@ -171,7 +171,7 @@ def test_apply_lang_metadata_has_no_warning_for_PageBreak(caplog):
         ("fr", "fra"),
     ],
 )
-def test_convert_language_code_to_pytesseract_lang_code(lang_in, expected_lang):
+def test_convert_language_code_to_pytesseract_lang_code(lang_in: str, expected_lang: str):
     assert expected_lang == _convert_language_code_to_pytesseract_lang_code(lang_in)
 
 
@@ -187,7 +187,7 @@ def test_convert_language_code_to_pytesseract_lang_code(lang_in, expected_lang):
         ("deu+spa", "deu+spa"),  # correct input
     ],
 )
-def test_clean_ocr_languages_arg(input_ocr_langs, expected):
+def test_clean_ocr_languages_arg(input_ocr_langs: str, expected: str):
     assert _clean_ocr_languages_arg(input_ocr_langs) == expected
 
 
@@ -209,12 +209,15 @@ def test_detect_languages_handles_spelled_out_languages():
     ],
 )
 def test_check_language_args_uses_languages_when_ocr_languages_and_languages_are_both_defined(
-    languages: Union[list[str], str],
-    ocr_languages: Union[list[str], str, None],
+    languages: list[str],
+    ocr_languages: list[str] | str,
     expected_langs: list[str],
-    caplog,
+    caplog: LogCaptureFixture,
 ):
-    returned_langs = check_language_args(languages=languages, ocr_languages=ocr_languages)
+    returned_langs = check_language_args(
+        languages=languages,
+        ocr_languages=ocr_languages,
+    )
     for lang in returned_langs:  # type: ignore
         assert lang in expected_langs
         assert "ocr_languages" in caplog.text
@@ -231,10 +234,10 @@ def test_check_language_args_uses_languages_when_ocr_languages_and_languages_are
     ],
 )
 def test_check_language_args_uses_ocr_languages_when_languages_is_empty_or_None(
-    languages: Union[list[str], str],
-    ocr_languages: Union[list[str], str, None],
+    languages: list[str],
+    ocr_languages: str,
     expected_langs: list[str],
-    caplog,
+    caplog: LogCaptureFixture,
 ):
     returned_langs = check_language_args(languages=languages, ocr_languages=ocr_languages)
     for lang in returned_langs:  # type: ignore
@@ -250,19 +253,15 @@ def test_check_language_args_uses_ocr_languages_when_languages_is_empty_or_None(
     ],
 )
 def test_check_language_args_returns_None(
-    languages: Union[list[str], str, None],
-    ocr_languages: Union[list[str], str, None],
+    languages: list[str],
+    ocr_languages: None,
 ):
     returned_langs = check_language_args(languages=languages, ocr_languages=ocr_languages)
     assert returned_langs is None
 
 
-def test_check_language_args_returns_auto(
-    languages=["eng", "spa", "auto"],
-    ocr_languages=None,
-):
-    returned_langs = check_language_args(languages=languages, ocr_languages=ocr_languages)
-    assert returned_langs == ["auto"]
+def test_check_language_args_returns_auto():
+    assert check_language_args(languages=["eng", "spa", "auto"], ocr_languages=None) == ["auto"]
 
 
 @pytest.mark.parametrize(
@@ -273,8 +272,11 @@ def test_check_language_args_returns_auto(
     ],
 )
 def test_check_language_args_raises_error_when_ocr_languages_contains_auto(
-    languages: Union[list[str], str, None],
-    ocr_languages: Union[list[str], str, None],
+    languages: list[str],
+    ocr_languages: str | list[str],
 ):
     with pytest.raises(ValueError):
-        check_language_args(languages=languages, ocr_languages=ocr_languages)
+        check_language_args(
+            languages=languages,
+            ocr_languages=ocr_languages,
+        )
diff --git a/test_unstructured/partition/common/test_metadata.py b/test_unstructured/partition/common/test_metadata.py
index 844486de89..345e55ae62 100644
--- a/test_unstructured/partition/common/test_metadata.py
+++ b/test_unstructured/partition/common/test_metadata.py
@@ -5,9 +5,13 @@
 import datetime as dt
 import os
 import pathlib
+from typing import Any, Callable
+
+import pytest
 
 from unstructured.documents.elements import (
     CheckBox,
+    Element,
     ElementMetadata,
     FigureCaption,
     Header,
@@ -16,7 +20,9 @@
     Text,
     Title,
 )
+from unstructured.file_utils.model import FileType
 from unstructured.partition.common.metadata import (
+    apply_metadata,
     get_last_modified_date,
     set_element_hierarchy,
 )
@@ -119,3 +125,193 @@ def test_set_element_hierarchy_custom_rule_set():
     assert (
         elements[5].metadata.parent_id == elements[4].id
     ), "FigureCaption should be child of Title 2"
+
+
+class Describe_apply_metadata:
+    """Unit-test suite for `unstructured.partition.common.metadata.apply_metadata()` decorator."""
+
+    # -- unique-ids -------------------------------------------------------
+
+    def it_assigns_hash_element_ids_when_unique_ids_arg_is_not_specified(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition()
+        elements_2 = partition()
+
+        # -- SHA1 hash is 32 characters long, no hyphens --
+        assert all(len(e.id) == 32 for e in elements)
+        assert all("-" not in e.id for e in elements)
+        # -- SHA1 hashes are deterministic --
+        assert all(e.id == e2.id for e, e2 in zip(elements, elements_2))
+
+    def it_assigns_hash_element_ids_when_unique_ids_arg_is_False(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition(unique_element_ids=False)
+        elements_2 = partition(unique_element_ids=False)
+
+        # -- SHA1 hash is 32 characters long, no hyphens --
+        assert all(len(e.id) == 32 for e in elements)
+        assert all("-" not in e.id for e in elements)
+        # -- SHA1 hashes are deterministic --
+        assert all(e.id == e2.id for e, e2 in zip(elements, elements_2))
+
+    def it_leaves_UUID_element_ids_when_unique_ids_arg_is_True(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition(unique_element_ids=True)
+        elements_2 = partition(unique_element_ids=True)
+
+        # -- UUID is 36 characters long with four hyphens --
+        assert all(len(e.id) == 36 for e in elements)
+        assert all(e.id.count("-") == 4 for e in elements)
+        # -- UUIDs are non-deterministic, different every time --
+        assert all(e.id != e2.id for e, e2 in zip(elements, elements_2))
+
+    # -- parent-id --------------------------------------------------------
+
+    def it_computes_and_assigns_parent_id(self, fake_partitioner: Callable[..., list[Element]]):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition()
+
+        title = elements[0]
+        assert title.metadata.category_depth == 1
+        narr_text = elements[1]
+        assert narr_text.metadata.parent_id == title.id
+
+    # -- languages --------------------------------------------------------
+
+    def it_applies_language_metadata(self, fake_partitioner: Callable[..., list[Element]]):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition(languages=["auto"], detect_language_per_element=True)
+
+        assert all(e.metadata.languages == ["eng"] for e in elements)
+
+    # -- filetype (MIME-type) ---------------------------------------------
+
+    def it_assigns_the_value_of_a_metadata_file_type_arg_when_there_is_one(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        """A `metadata_file_type` arg overrides the file-type specified in the decorator.
+
+        This is used for example by a delegating partitioner to preserve the original file-type in
+        the metadata, like EPUB instead of the HTML that partitioner converts the .epub file to.
+        """
+        partition = apply_metadata(file_type=FileType.DOCX)(fake_partitioner)
+
+        elements = partition(metadata_file_type=FileType.ODT)
+
+        assert all(
+            e.metadata.filetype == "application/vnd.oasis.opendocument.text" for e in elements
+        )
+
+    def and_it_assigns_the_decorator_file_type_when_the_metadata_file_type_arg_is_omitted(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        """The `file_type=...` decorator arg is the "normal" way to specify the file-type.
+
+        This is used for principal (non-delegating) partitioners.
+        """
+        partition = apply_metadata(file_type=FileType.DOCX)(fake_partitioner)
+
+        elements = partition()
+
+        DOCX_MIME_TYPE = "application/vnd.openxmlformats-officedocument.wordprocessingml.document"
+        assert all(e.metadata.filetype == DOCX_MIME_TYPE for e in elements)
+
+    def and_it_does_not_assign_file_type_metadata_when_both_are_omitted(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        """A partitioner can elect to assign `.metadata.filetype` for itself.
+
+        This is done in `partition_image()` for example where the same partitioner is used for
+        multiple file-types.
+        """
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition()
+
+        assert all(e.metadata.filetype == "image/jpeg" for e in elements)
+
+    # -- filename ---------------------------------------------------------
+
+    def it_uses_metadata_filename_arg_value_when_present(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        """A `metadata_filename` arg overrides all other sources."""
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition(metadata_filename="a/b/c.xyz")
+
+        assert all(e.metadata.filename == "c.xyz" for e in elements)
+        assert all(e.metadata.file_directory == "a/b" for e in elements)
+
+    def and_it_uses_filename_arg_value_when_metadata_filename_arg_not_present(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition(filename="a/b/c.xyz")
+
+        assert all(e.metadata.filename == "c.xyz" for e in elements)
+        assert all(e.metadata.file_directory == "a/b" for e in elements)
+
+    def and_it_does_not_assign_filename_metadata_when_neither_are_present(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition()
+
+        assert all(e.metadata.filename == "image.jpeg" for e in elements)
+        assert all(e.metadata.file_directory == "x/y/images" for e in elements)
+
+    # -- url --------------------------------------------------------------
+
+    def it_assigns_url_metadata_field_when_url_arg_is_present(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition(url="https://adobe.com/stock/54321")
+
+        assert all(e.metadata.url == "https://adobe.com/stock/54321" for e in elements)
+
+    def and_it_does_not_assign_url_metadata_when_url_arg_is_not_present(
+        self, fake_partitioner: Callable[..., list[Element]]
+    ):
+        partition = apply_metadata()(fake_partitioner)
+
+        elements = partition()
+
+        assert all(e.metadata.url == "http://images.com" for e in elements)
+
+    # -- fixtures --------------------------------------------------------------------------------
+
+    @pytest.fixture
+    def fake_partitioner(self) -> Callable[..., list[Element]]:
+        def fake_partitioner(**kwargs: Any) -> list[Element]:
+            title = Title("Introduction")
+            title.metadata.category_depth = 1
+            title.metadata.file_directory = "x/y/images"
+            title.metadata.filename = "image.jpeg"
+            title.metadata.filetype = "image/jpeg"
+            title.metadata.url = "http://images.com"
+
+            narr_text = NarrativeText("To understand bar you must first understand foo.")
+            narr_text.metadata.file_directory = "x/y/images"
+            narr_text.metadata.filename = "image.jpeg"
+            narr_text.metadata.filetype = "image/jpeg"
+            narr_text.metadata.url = "http://images.com"
+
+            return [title, narr_text]
+
+        return fake_partitioner
diff --git a/unstructured/__version__.py b/unstructured/__version__.py
index 97668e6dc0..18a138fccd 100644
--- a/unstructured/__version__.py
+++ b/unstructured/__version__.py
@@ -1 +1 @@
-__version__ = "0.15.14-dev3"  # pragma: no cover
+__version__ = "0.15.14-dev4"  # pragma: no cover
diff --git a/unstructured/partition/auto.py b/unstructured/partition/auto.py
index a9f033ce12..b5e95f2e85 100644
--- a/unstructured/partition/auto.py
+++ b/unstructured/partition/auto.py
@@ -14,7 +14,7 @@
 from unstructured.file_utils.model import FileType
 from unstructured.logger import logger
 from unstructured.partition.common.common import exactly_one
-from unstructured.partition.lang import check_language_args
+from unstructured.partition.common.lang import check_language_args
 from unstructured.partition.utils.constants import PartitionStrategy
 from unstructured.utils import dependency_exists
 
diff --git a/unstructured/partition/lang.py b/unstructured/partition/common/lang.py
similarity index 93%
rename from unstructured/partition/lang.py
rename to unstructured/partition/common/lang.py
index d91d648829..d73d5cb921 100644
--- a/unstructured/partition/lang.py
+++ b/unstructured/partition/common/lang.py
@@ -3,8 +3,12 @@
 import re
 from typing import Iterable, Iterator, Optional
 
-import iso639
-from langdetect import DetectorFactory, detect_langs, lang_detect_exception
+import iso639  # pyright: ignore[reportMissingTypeStubs]
+from langdetect import (  # pyright: ignore[reportMissingTypeStubs]
+    DetectorFactory,
+    detect_langs,  # pyright: ignore[reportUnknownVariableType]
+    lang_detect_exception,
+)
 
 from unstructured.documents.elements import Element
 from unstructured.logger import logger
@@ -208,12 +212,13 @@ def prepare_languages_for_tesseract(languages: Optional[list[str]] = ["eng"]) ->
     """
     if languages is None:
         raise ValueError("`languages` can not be `None`")
-    converted_languages = list(
-        filter(
-            lambda x: x is not None and x != "",
-            [_convert_language_code_to_pytesseract_lang_code(lang) for lang in languages],
-        ),
-    )
+    converted_languages = [
+        lang_code
+        for lang_code in (
+            _convert_language_code_to_pytesseract_lang_code(lang) for lang in languages
+        )
+        if lang_code
+    ]
     # Remove duplicates from the list but keep the original order
     converted_languages = list(dict.fromkeys(converted_languages))
     if len(converted_languages) == 0:
@@ -245,13 +250,17 @@ def tesseract_to_paddle_language(tesseract_language: str) -> str:
     return lang
 
 
-def check_language_args(languages: list[str], ocr_languages: Optional[str]) -> Optional[list[str]]:
-    """Handle users defining both `ocr_languages` and `languages`, giving preference to `languages`
-    and converting `ocr_languages` if needed, but defaulting to `None.
+def check_language_args(
+    languages: list[str], ocr_languages: str | list[str] | None
+) -> list[str] | None:
+    """Handle users defining both `ocr_languages` and `languages`.
+
+    Give preference to `languages` and convert `ocr_languages` if needed, but default to `None`.
 
     `ocr_languages` is only a parameter for `auto.partition`, `partition_image`, & `partition_pdf`.
     `ocr_languages` should not be defined as 'auto' since 'auto' is intended for language detection
-    which is not supported by `partition_image` or `partition_pdf`."""
+    which is not supported by `partition_image` or `partition_pdf`.
+    """
     # --- Clean and update defaults
     if ocr_languages:
         ocr_languages = _clean_ocr_languages_arg(ocr_languages)
@@ -259,6 +268,7 @@ def check_language_args(languages: list[str], ocr_languages: Optional[str]) -> O
             "The ocr_languages kwarg will be deprecated in a future version of unstructured. "
             "Please use languages instead.",
         )
+    assert ocr_languages is None or isinstance(ocr_languages, str)
 
     if ocr_languages and "auto" in ocr_languages:
         raise ValueError(
@@ -268,7 +278,7 @@ def check_language_args(languages: list[str], ocr_languages: Optional[str]) -> O
             " Language detection is not currently supported in pdfs or images."
         )
 
-    if not isinstance(languages, list):
+    if not isinstance(languages, list):  # pyright: ignore[reportUnnecessaryIsInstance]
         raise TypeError(
             "The language parameter must be a list of language codes as strings, ex. ['eng']",
         )
@@ -354,7 +364,7 @@ def _convert_language_code_to_pytesseract_lang_code(lang: str) -> str:
 
 def _get_iso639_language_object(lang: str) -> Optional[iso639.Language]:
     try:
-        return iso639.Language.match(lang.lower())
+        return iso639.Language.match(lang.lower())  # pyright: ignore[reportUnknownMemberType]
     except iso639.LanguageNotFoundError:
         logger.warning(f"{lang} is not a valid standard language code.")
         return None
@@ -431,10 +441,10 @@ def detect_languages(
         # machine translation
         # TODO(shreya): decide how to maintain nonstandard chinese script information
         for langobj in langdetect_result:
-            if str(langobj.lang).startswith("zh"):
+            if str(langobj.lang).startswith("zh"):  # pyright: ignore
                 langdetect_langs.append("zho")
             else:
-                language = _get_iso639_language_object(langobj.lang[:3])
+                language = _get_iso639_language_object(langobj.lang[:3])  # pyright: ignore
                 if language:
                     langdetect_langs.append(language.part3)
 
diff --git a/unstructured/partition/common/metadata.py b/unstructured/partition/common/metadata.py
index f783096a3d..7de1909a37 100644
--- a/unstructured/partition/common/metadata.py
+++ b/unstructured/partition/common/metadata.py
@@ -3,13 +3,21 @@
 from __future__ import annotations
 
 import datetime as dt
+import functools
 import os
-from typing import Optional, Sequence
+from typing import Any, Callable, Sequence
 
-from unstructured.documents.elements import Element
+from typing_extensions import ParamSpec
 
+from unstructured.documents.elements import Element, ElementMetadata, assign_and_map_hash_ids
+from unstructured.file_utils.model import FileType
+from unstructured.partition.common.lang import apply_lang_metadata
+from unstructured.utils import get_call_args_applying_defaults
 
-def get_last_modified_date(filename: str) -> Optional[str]:
+_P = ParamSpec("_P")
+
+
+def get_last_modified_date(filename: str) -> str | None:
     """Modification time of file at path `filename`, if it exists.
 
     Returns `None` when `filename` is not a path to a file on the local filesystem.
@@ -54,9 +62,9 @@ def get_last_modified_date(filename: str) -> Optional[str]:
 def set_element_hierarchy(
     elements: Sequence[Element], ruleset: dict[str, list[str]] = HIERARCHY_RULE_SET
 ) -> list[Element]:
-    """Sets the parent_id for each element in the list of elements
-    based on the element's category, depth and a ruleset
+    """Sets `.metadata.parent_id` for each element it applies to.
 
+    `parent_id` assignment is based on the element's category, depth and a ruleset.
     """
     stack: list[Element] = []
     for element in elements:
@@ -97,3 +105,104 @@ def set_element_hierarchy(
         stack.append(element)
 
     return list(elements)
+
+
+# ================================================================================================
+# METADATA POST-PARTITIONING PROCESSING DECORATOR
+# ================================================================================================
+
+
+def apply_metadata(
+    file_type: FileType | None = None,
+) -> Callable[[Callable[_P, list[Element]]], Callable[_P, list[Element]]]:
+    """Post-process element-metadata for this document.
+
+    This decorator adds a post-processing step to a partitioner, primarily to apply metadata that
+    is common to all partitioners. It assumes the following responsibilities:
+
+      - Hash element-ids. Computes and applies SHA1 hash element.id when `unique_element_ids`
+        argument is False.
+
+      - Element Hierarchy. Computes and applies `parent_id` metadata based on `category_depth`
+        etc. added by partitioner.
+
+      - Language metadata. Computes and applies `language` metadata based on a language detection
+        model.
+
+      - Apply `filetype` (MIME-type) metadata. There are three cases; first one in this order that
+        applies is used:
+
+          - `metadata_file_type` argument is present in call, use that.
+          - `file_type` decorator argument is populated, use that.
+          - `file_type` decorator argument is omitted or None, don't apply `.metadata.filetype`
+            (assume the partitioner will do that for itself, like `partition_image()`.
+
+      - Replace `filename` with `metadata_filename` when present.
+
+      - Apply `url` metadata when present.
+    """
+
+    def decorator(func: Callable[_P, list[Element]]) -> Callable[_P, list[Element]]:
+        """The decorator function itself.
+
+        This function is returned by the `apply_metadata()` function and is the actual decorator.
+        Think of `apply_metadata()` as a factory function that configures this decorator, in
+        particular by setting its `file_type` value.
+        """
+
+        @functools.wraps(func)
+        def wrapper(*args: _P.args, **kwargs: _P.kwargs) -> list[Element]:
+            elements = func(*args, **kwargs)
+            call_args = get_call_args_applying_defaults(func, *args, **kwargs)
+
+            # -- Compute and apply hash-ids if the user does not want UUIDs. Note this changes the
+            # -- elements themselves, not the metadata.
+            unique_element_ids: bool = call_args.get("unique_element_ids", False)
+            if unique_element_ids is False:
+                elements = assign_and_map_hash_ids(elements)
+
+            # -- `parent_id` - process category-level etc. to assign parent-id --
+            elements = set_element_hierarchy(elements)
+
+            # -- `language` - auto-detect language (e.g. eng, spa) --
+            languages = call_args.get("languages")
+            detect_language_per_element = call_args.get("detect_language_per_element", False)
+            elements = list(
+                apply_lang_metadata(
+                    elements=elements,
+                    languages=languages,
+                    detect_language_per_element=detect_language_per_element,
+                )
+            )
+
+            # == apply filetype, filename, and url metadata =========================
+            metadata_kwargs: dict[str, Any] = {}
+
+            # -- `filetype` (MIME-type) metadata --
+            metadata_file_type = call_args.get("metadata_file_type") or file_type
+            if metadata_file_type is not None:
+                metadata_kwargs["filetype"] = metadata_file_type.mime_type
+
+            # -- `filename` metadata - override with metadata_filename when it's present --
+            filename = call_args.get("metadata_filename") or call_args.get("filename")
+            if filename:
+                metadata_kwargs["filename"] = filename
+
+            # -- `url` metadata - record url when present --
+            url = call_args.get("url")
+            if url:
+                metadata_kwargs["url"] = url
+
+            # -- update element.metadata in single pass --
+            for element in elements:
+                # NOTE(robinson) - Attached files have already run through this logic in their own
+                # partitioning function
+                if element.metadata.attached_to_filename:
+                    continue
+                element.metadata.update(ElementMetadata(**metadata_kwargs))
+
+            return elements
+
+        return wrapper
+
+    return decorator
diff --git a/unstructured/partition/csv.py b/unstructured/partition/csv.py
index 5b228da656..9e2975dcfa 100644
--- a/unstructured/partition/csv.py
+++ b/unstructured/partition/csv.py
@@ -16,8 +16,8 @@
 )
 from unstructured.file_utils.filetype import add_metadata_with_filetype
 from unstructured.file_utils.model import FileType
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.utils import is_temp_file_path, lazyproperty
 
 DETECTION_ORIGIN: str = "csv"
diff --git a/unstructured/partition/docx.py b/unstructured/partition/docx.py
index 53490f2cfd..89889621a8 100644
--- a/unstructured/partition/docx.py
+++ b/unstructured/partition/docx.py
@@ -46,8 +46,8 @@
 )
 from unstructured.file_utils.filetype import add_metadata_with_filetype
 from unstructured.file_utils.model import FileType
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text_type import (
     is_bulleted_text,
     is_email_address,
diff --git a/unstructured/partition/email.py b/unstructured/partition/email.py
index 6e3b6ab74b..b6508eddd7 100644
--- a/unstructured/partition/email.py
+++ b/unstructured/partition/email.py
@@ -47,9 +47,9 @@
 from unstructured.logger import logger
 from unstructured.nlp.patterns import EMAIL_DATETIMETZ_PATTERN_RE
 from unstructured.partition.common.common import convert_to_bytes, exactly_one
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
 from unstructured.partition.html import partition_html
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text import partition_text
 
 VALID_CONTENT_SOURCES: Final[list[str]] = ["text/html", "text/plain"]
@@ -101,7 +101,7 @@ def append_address_header_elements(header: AddressHeader, element_type: Type[Ele
         for addr in header.addresses:
             elements.append(
                 element_type(
-                    name=addr.display_name or addr.username,
+                    name=addr.display_name or addr.username,  # type: ignore
                     text=addr.addr_spec,  # type: ignore
                 )
             )
diff --git a/unstructured/partition/html/partition.py b/unstructured/partition/html/partition.py
index 8983f39b4d..a4e695cf7a 100644
--- a/unstructured/partition/html/partition.py
+++ b/unstructured/partition/html/partition.py
@@ -14,9 +14,9 @@
 from unstructured.file_utils.encoding import read_txt_file
 from unstructured.file_utils.filetype import add_metadata_with_filetype
 from unstructured.file_utils.model import FileType
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
 from unstructured.partition.html.parser import Flow, html_parser
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.utils import is_temp_file_path, lazyproperty
 
 
diff --git a/unstructured/partition/image.py b/unstructured/partition/image.py
index c5fae5a9c7..50ceaa1187 100644
--- a/unstructured/partition/image.py
+++ b/unstructured/partition/image.py
@@ -6,7 +6,7 @@
 from unstructured.documents.elements import Element, process_metadata
 from unstructured.file_utils.filetype import add_metadata
 from unstructured.partition.common.common import exactly_one
-from unstructured.partition.lang import check_language_args
+from unstructured.partition.common.lang import check_language_args
 from unstructured.partition.pdf import partition_pdf_or_image
 from unstructured.partition.utils.constants import PartitionStrategy
 
diff --git a/unstructured/partition/msg.py b/unstructured/partition/msg.py
index 8ce7e5880a..0641c662bb 100644
--- a/unstructured/partition/msg.py
+++ b/unstructured/partition/msg.py
@@ -14,9 +14,9 @@
 from unstructured.file_utils.filetype import add_metadata_with_filetype
 from unstructured.file_utils.model import FileType
 from unstructured.logger import logger
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
 from unstructured.partition.html import partition_html
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text import partition_text
 from unstructured.utils import is_temp_file_path, lazyproperty
 
diff --git a/unstructured/partition/pdf.py b/unstructured/partition/pdf.py
index bb276fc194..1f8300ce37 100644
--- a/unstructured/partition/pdf.py
+++ b/unstructured/partition/pdf.py
@@ -48,12 +48,12 @@
     ocr_data_to_elements,
     spooled_to_bytes_io_if_needed,
 )
-from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import (
+from unstructured.partition.common.lang import (
     check_language_args,
     prepare_languages_for_tesseract,
     tesseract_to_paddle_language,
 )
+from unstructured.partition.common.metadata import get_last_modified_date
 from unstructured.partition.pdf_image.analysis.layout_dump import (
     ExtractedLayoutDumper,
     FinalLayoutDumper,
diff --git a/unstructured/partition/pptx.py b/unstructured/partition/pptx.py
index b856adf977..df24daac00 100644
--- a/unstructured/partition/pptx.py
+++ b/unstructured/partition/pptx.py
@@ -37,8 +37,8 @@
 from unstructured.file_utils.filetype import add_metadata_with_filetype
 from unstructured.file_utils.model import FileType
 from unstructured.partition.common.common import convert_ms_office_table_to_text
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text_type import (
     is_email_address,
     is_possible_narrative_text,
diff --git a/unstructured/partition/text.py b/unstructured/partition/text.py
index ef50ab6b5b..12df9abd5e 100644
--- a/unstructured/partition/text.py
+++ b/unstructured/partition/text.py
@@ -30,8 +30,8 @@
 from unstructured.nlp.patterns import PARAGRAPH_PATTERN, UNICODE_BULLETS_RE
 from unstructured.nlp.tokenize import sent_tokenize
 from unstructured.partition.common.common import exactly_one
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text_type import (
     is_bulleted_text,
     is_email_address,
diff --git a/unstructured/partition/tsv.py b/unstructured/partition/tsv.py
index 8509a337d9..72c0984e4e 100644
--- a/unstructured/partition/tsv.py
+++ b/unstructured/partition/tsv.py
@@ -18,8 +18,8 @@
     exactly_one,
     spooled_to_bytes_io_if_needed,
 )
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 
 DETECTION_ORIGIN: str = "tsv"
 
diff --git a/unstructured/partition/xlsx.py b/unstructured/partition/xlsx.py
index c6d516ee5e..7f6e93eca5 100644
--- a/unstructured/partition/xlsx.py
+++ b/unstructured/partition/xlsx.py
@@ -26,8 +26,8 @@
 )
 from unstructured.file_utils.filetype import add_metadata_with_filetype
 from unstructured.file_utils.model import FileType
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text_type import (
     is_bulleted_text,
     is_possible_narrative_text,
diff --git a/unstructured/partition/xml.py b/unstructured/partition/xml.py
index f9cca71a27..1ed30966b9 100644
--- a/unstructured/partition/xml.py
+++ b/unstructured/partition/xml.py
@@ -20,8 +20,8 @@
     exactly_one,
     spooled_to_bytes_io_if_needed,
 )
+from unstructured.partition.common.lang import apply_lang_metadata
 from unstructured.partition.common.metadata import get_last_modified_date
-from unstructured.partition.lang import apply_lang_metadata
 from unstructured.partition.text import element_from_text
 
 DETECTION_ORIGIN: str = "xml"