diff --git a/STYLE-GUIDE.md b/STYLE-GUIDE.md
new file mode 100644
index 0000000000..96180170da
--- /dev/null
+++ b/STYLE-GUIDE.md
@@ -0,0 +1,23 @@
+# Exercism's Style Guide
+
+This document acts as a Style Guide for the language and wording used in exercises.
+
+## General principle
+
+All content should be written in US English.
+All units of measurement must be [SI](https://en.wikipedia.org/wiki/International_System_of_Units) or [SI-derived](https://en.wikipedia.org/wiki/SI_derived_unit) units.
+In the future other translations may occur, but the "official" Exercism language is US English.
+
+## Explain or substitute mathematical and esoteric terms.
+
+In any place that mathematical terms are used they should be explained or substituted out for terms that require less domain knowledge.
+
+Examples:
+- Rather than using "natural numbers", we should use "positive whole numbers".
+- If we want to use the phrase "rational numbers", it must be explained in the introduction to the exercise.
+- Rather than using the word range (which can have different meanings in different contexts) use "x < ? < y (greater than x and less than y)".
+
+## Use consistency within an exercise.
+
+There are some terms that have multiple valid spellings (e.g. "lower case" vs "lowercase"). 
+Where a consistent style has not been agreed within this document, these must be consistent within an exercise.