diff --git a/apps/mark-scan/backend/schema.sql b/apps/mark-scan/backend/schema.sql
index f5600df7a7..649b01a668 100644
--- a/apps/mark-scan/backend/schema.sql
+++ b/apps/mark-scan/backend/schema.sql
@@ -12,3 +12,27 @@ create table system_settings (
   id integer primary key check (id = 1),
   data text not null -- JSON blob
 );
+
+create table languages (
+  code text primary key
+);
+
+create table ui_strings (
+  language_code text primary key,
+  data text not null, -- JSON blob - see libs/types/UiStringTranslationsSchema
+  foreign key (language_code) references languages(code)
+);
+
+create table audio_clips (
+  id text not null,
+  language_code text not null,
+  data_base64 text not null, -- Base64-encoded audio bytes
+  primary key (language_code, id),
+  foreign key (language_code) references languages(code)
+);
+
+create table ui_string_audio_keys (
+  language_code text primary key,
+  data text not null, -- JSON blob - see libs/types/UiStringAudioKeysSchema
+  foreign key (language_code) references languages(code)
+);
diff --git a/apps/mark-scan/backend/src/app.test.ts b/apps/mark-scan/backend/src/app.test.ts
index 573a52cb49..13db44e4f5 100644
--- a/apps/mark-scan/backend/src/app.test.ts
+++ b/apps/mark-scan/backend/src/app.test.ts
@@ -62,6 +62,7 @@ beforeEach(async () => {
 afterEach(() => {
   stateMachine.stopMachineService();
   server?.close();
+  jest.resetAllMocks();
 });
 
 async function setUpUsbAndConfigureElection(
diff --git a/apps/mark-scan/backend/src/app.ts b/apps/mark-scan/backend/src/app.ts
index 1c80dddd1c..e6033e4102 100644
--- a/apps/mark-scan/backend/src/app.ts
+++ b/apps/mark-scan/backend/src/app.ts
@@ -20,7 +20,11 @@ import {
   singlePrecinctSelectionFor,
 } from '@votingworks/utils';
 
-import { Usb, readBallotPackageFromUsb } from '@votingworks/backend';
+import {
+  createUiStringsApi,
+  Usb,
+  readBallotPackageFromUsb,
+} from '@votingworks/backend';
 import { Logger } from '@votingworks/logging';
 import { electionGeneralDefinition } from '@votingworks/fixtures';
 import { useDevDockRouter } from '@votingworks/dev-dock-backend';
@@ -36,7 +40,8 @@ const debug = makeDebug('mark-scan:app-backend');
 
 const defaultMediaMountDir = '/media';
 
-function buildApi(
+// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+export function buildApi(
   auth: InsertedSmartCardAuthApi,
   usb: Usb,
   logger: Logger,
@@ -232,6 +237,11 @@ function buildApi(
 
       stateMachine.confirmInvalidateBallot();
     },
+
+    ...createUiStringsApi({
+      logger,
+      store: workspace.store.getUiStringsStore(),
+    }),
   });
 }
 
diff --git a/apps/mark-scan/backend/src/app.ui_strings.test.ts b/apps/mark-scan/backend/src/app.ui_strings.test.ts
new file mode 100644
index 0000000000..cc4fdc1d6f
--- /dev/null
+++ b/apps/mark-scan/backend/src/app.ui_strings.test.ts
@@ -0,0 +1,26 @@
+import tmp from 'tmp';
+
+import { createMockUsb, runUiStringApiTests } from '@votingworks/backend';
+import { fakeLogger } from '@votingworks/logging';
+
+import { buildMockInsertedSmartCardAuth } from '@votingworks/auth';
+import { Store } from './store';
+import { createWorkspace } from './util/workspace';
+import { buildApi } from './app';
+
+const store = Store.memoryStore();
+const workspace = createWorkspace(tmp.dirSync().name, { store });
+
+afterAll(() => {
+  workspace.reset();
+});
+
+runUiStringApiTests({
+  api: buildApi(
+    buildMockInsertedSmartCardAuth(),
+    createMockUsb().mock,
+    fakeLogger(),
+    workspace
+  ),
+  store: store.getUiStringsStore(),
+});
diff --git a/apps/mark-scan/backend/src/store.ts b/apps/mark-scan/backend/src/store.ts
index 553823868c..a3a615e109 100644
--- a/apps/mark-scan/backend/src/store.ts
+++ b/apps/mark-scan/backend/src/store.ts
@@ -2,6 +2,7 @@
 // The durable datastore for configuration info.
 //
 
+import { UiStringsStore, createUiStringStore } from '@votingworks/backend';
 import { Optional } from '@votingworks/basics';
 import { Client as DbClient } from '@votingworks/db';
 import {
@@ -21,7 +22,10 @@ const SchemaPath = join(__dirname, '../schema.sql');
  * Manages a data store for imported election definition and system settings
  */
 export class Store {
-  private constructor(private readonly client: DbClient) {}
+  private constructor(
+    private readonly client: DbClient,
+    private readonly uiStringsStore: UiStringsStore
+  ) {}
 
   getDbPath(): string {
     return this.client.getDatabasePath();
@@ -31,14 +35,18 @@ export class Store {
    * Builds and returns a new store whose data is kept in memory.
    */
   static memoryStore(): Store {
-    return new Store(DbClient.memoryClient(SchemaPath));
+    const client = DbClient.memoryClient(SchemaPath);
+    const uiStringsStore = createUiStringStore(client);
+    return new Store(client, uiStringsStore);
   }
 
   /**
    * Builds and returns a new store at `dbPath`.
    */
   static fileStore(dbPath: string): Store {
-    return new Store(DbClient.fileClient(dbPath, SchemaPath));
+    const client = DbClient.fileClient(dbPath, SchemaPath);
+    const uiStringsStore = createUiStringStore(client);
+    return new Store(client, uiStringsStore);
   }
 
   /**
@@ -184,4 +192,8 @@ export class Store {
     if (!result) return undefined;
     return safeParseSystemSettings(result.data).unsafeUnwrap();
   }
+
+  getUiStringsStore(): UiStringsStore {
+    return this.uiStringsStore;
+  }
 }
diff --git a/apps/mark-scan/backend/src/util/workspace.ts b/apps/mark-scan/backend/src/util/workspace.ts
index d3a5436d0a..7ce8988205 100644
--- a/apps/mark-scan/backend/src/util/workspace.ts
+++ b/apps/mark-scan/backend/src/util/workspace.ts
@@ -36,12 +36,15 @@ export function constructAuthMachineState(
   };
 }
 
-export function createWorkspace(root: string): Workspace {
+export function createWorkspace(
+  root: string,
+  options: { store?: Store } = {}
+): Workspace {
   const resolvedRoot = resolve(root);
   ensureDirSync(resolvedRoot);
 
   const dbPath = join(resolvedRoot, 'mark.db');
-  const store = Store.fileStore(dbPath);
+  const store = options.store || Store.fileStore(dbPath);
 
   return {
     path: resolvedRoot,
diff --git a/apps/mark/backend/schema.sql b/apps/mark/backend/schema.sql
index f5de6718a2..a275fabdc0 100644
--- a/apps/mark/backend/schema.sql
+++ b/apps/mark/backend/schema.sql
@@ -11,3 +11,27 @@ create table system_settings (
   id integer primary key check (id = 1),
   data text not null -- JSON blob
 );
+
+create table languages (
+  code text primary key
+);
+
+create table ui_strings (
+  language_code text primary key,
+  data text not null, -- JSON blob - see libs/types/UiStringTranslationsSchema
+  foreign key (language_code) references languages(code)
+);
+
+create table audio_clips (
+  id text not null,
+  language_code text not null,
+  data_base64 text not null, -- Base64-encoded audio bytes
+  primary key (language_code, id),
+  foreign key (language_code) references languages(code)
+);
+
+create table ui_string_audio_keys (
+  language_code text primary key,
+  data text not null, -- JSON blob - see libs/types/UiStringAudioKeysSchema
+  foreign key (language_code) references languages(code)
+);
diff --git a/apps/mark/backend/src/app.ts b/apps/mark/backend/src/app.ts
index f1adaff7cb..3a588444cc 100644
--- a/apps/mark/backend/src/app.ts
+++ b/apps/mark/backend/src/app.ts
@@ -16,7 +16,11 @@ import {
 } from '@votingworks/types';
 import { isElectionManagerAuth } from '@votingworks/utils';
 
-import { Usb, readBallotPackageFromUsb } from '@votingworks/backend';
+import {
+  createUiStringsApi,
+  Usb,
+  readBallotPackageFromUsb,
+} from '@votingworks/backend';
 import { Logger } from '@votingworks/logging';
 import { electionGeneralDefinition } from '@votingworks/fixtures';
 import { useDevDockRouter } from '@votingworks/dev-dock-backend';
@@ -37,7 +41,8 @@ function constructAuthMachineState(
   };
 }
 
-function buildApi(
+// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+export function buildApi(
   auth: InsertedSmartCardAuthApi,
   usb: Usb,
   logger: Logger,
@@ -139,6 +144,11 @@ function buildApi(
 
       return ok(electionDefinition);
     },
+
+    ...createUiStringsApi({
+      logger,
+      store: workspace.store.getUiStringsStore(),
+    }),
   });
 }
 
diff --git a/apps/mark/backend/src/app.ui_strings.test.ts b/apps/mark/backend/src/app.ui_strings.test.ts
new file mode 100644
index 0000000000..45b6498851
--- /dev/null
+++ b/apps/mark/backend/src/app.ui_strings.test.ts
@@ -0,0 +1,22 @@
+import tmp from 'tmp';
+
+import { createMockUsb, runUiStringApiTests } from '@votingworks/backend';
+import { fakeLogger } from '@votingworks/logging';
+
+import { buildMockInsertedSmartCardAuth } from '@votingworks/auth';
+import { Store } from './store';
+import { createWorkspace } from './util/workspace';
+import { buildApi } from './app';
+
+const store = Store.memoryStore();
+const workspace = createWorkspace(tmp.dirSync().name, { store });
+
+runUiStringApiTests({
+  api: buildApi(
+    buildMockInsertedSmartCardAuth(),
+    createMockUsb().mock,
+    fakeLogger(),
+    workspace
+  ),
+  store: store.getUiStringsStore(),
+});
diff --git a/apps/mark/backend/src/store.ts b/apps/mark/backend/src/store.ts
index 4fbe5f00de..298fb4956d 100644
--- a/apps/mark/backend/src/store.ts
+++ b/apps/mark/backend/src/store.ts
@@ -2,6 +2,7 @@
 // The durable datastore for configuration info.
 //
 
+import { UiStringsStore, createUiStringStore } from '@votingworks/backend';
 import { Client as DbClient } from '@votingworks/db';
 import {
   ElectionDefinition,
@@ -17,7 +18,10 @@ const SchemaPath = join(__dirname, '../schema.sql');
  * Manages a data store for imported election definition and system settings
  */
 export class Store {
-  private constructor(private readonly client: DbClient) {}
+  private constructor(
+    private readonly client: DbClient,
+    private readonly uiStringsStore: UiStringsStore
+  ) {}
 
   getDbPath(): string {
     return this.client.getDatabasePath();
@@ -27,14 +31,18 @@ export class Store {
    * Builds and returns a new store whose data is kept in memory.
    */
   static memoryStore(): Store {
-    return new Store(DbClient.memoryClient(SchemaPath));
+    const client = DbClient.memoryClient(SchemaPath);
+    const uiStringsStore = createUiStringStore(client);
+    return new Store(client, uiStringsStore);
   }
 
   /**
    * Builds and returns a new store at `dbPath`.
    */
   static fileStore(dbPath: string): Store {
-    return new Store(DbClient.fileClient(dbPath, SchemaPath));
+    const client = DbClient.fileClient(dbPath, SchemaPath);
+    const uiStringsStore = createUiStringStore(client);
+    return new Store(client, uiStringsStore);
   }
 
   /**
@@ -139,4 +147,8 @@ export class Store {
     if (!result) return undefined;
     return safeParseSystemSettings(result.data).unsafeUnwrap();
   }
+
+  getUiStringsStore(): UiStringsStore {
+    return this.uiStringsStore;
+  }
 }
diff --git a/apps/mark/backend/src/util/workspace.ts b/apps/mark/backend/src/util/workspace.ts
index 90adf379ab..c3d885f9a5 100644
--- a/apps/mark/backend/src/util/workspace.ts
+++ b/apps/mark/backend/src/util/workspace.ts
@@ -20,12 +20,15 @@ export interface Workspace {
   reset(): void;
 }
 
-export function createWorkspace(root: string): Workspace {
+export function createWorkspace(
+  root: string,
+  options: { store?: Store } = {}
+): Workspace {
   const resolvedRoot = resolve(root);
   ensureDirSync(resolvedRoot);
 
   const dbPath = join(resolvedRoot, 'mark.db');
-  const store = Store.fileStore(dbPath);
+  const store = options.store || Store.fileStore(dbPath);
 
   return {
     path: resolvedRoot,
diff --git a/apps/scan/backend/schema.sql b/apps/scan/backend/schema.sql
index 9a25064cbe..164e1fdde7 100644
--- a/apps/scan/backend/schema.sql
+++ b/apps/scan/backend/schema.sql
@@ -87,3 +87,27 @@ create unique index idx_cvr_hashes ON cvr_hashes (
   cvr_id_level_2_prefix,
   cvr_id
 );
+
+create table languages (
+  code text primary key
+);
+
+create table ui_strings (
+  language_code text primary key,
+  data text not null, -- JSON blob - see libs/types/UiStringTranslationsSchema
+  foreign key (language_code) references languages(code)
+);
+
+create table audio_clips (
+  id text not null,
+  language_code text not null,
+  data_base64 text not null, -- Base64-encoded audio bytes
+  primary key (language_code, id),
+  foreign key (language_code) references languages(code)
+);
+
+create table ui_string_audio_keys (
+  language_code text primary key,
+  data text not null, -- JSON blob - see libs/types/UiStringAudioKeysSchema
+  foreign key (language_code) references languages(code)
+);
diff --git a/apps/scan/backend/src/app.ts b/apps/scan/backend/src/app.ts
index 380c4441ea..171673ba41 100644
--- a/apps/scan/backend/src/app.ts
+++ b/apps/scan/backend/src/app.ts
@@ -17,6 +17,7 @@ import {
 } from '@votingworks/utils';
 import express, { Application } from 'express';
 import {
+  createUiStringsApi,
   ExportDataError,
   exportCastVoteRecordReportToUsbDrive,
   ExportCastVoteRecordReportToUsbDriveError,
@@ -55,7 +56,8 @@ function constructAuthMachineState(
   };
 }
 
-function buildApi(
+// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+export function buildApi(
   auth: InsertedSmartCardAuthApi,
   machine: PrecinctScannerStateMachine,
   workspace: Workspace,
@@ -367,6 +369,11 @@ function buildApi(
     supportsUltrasonic(): boolean {
       return machine.supportsUltrasonic();
     },
+
+    ...createUiStringsApi({
+      logger,
+      store: workspace.store.getUiStringsStore(),
+    }),
   });
 }
 
diff --git a/apps/scan/backend/src/app_ui_strings.test.ts b/apps/scan/backend/src/app_ui_strings.test.ts
new file mode 100644
index 0000000000..b52678b689
--- /dev/null
+++ b/apps/scan/backend/src/app_ui_strings.test.ts
@@ -0,0 +1,35 @@
+import tmp from 'tmp';
+
+import { runUiStringApiTests } from '@votingworks/backend';
+import { buildMockInsertedSmartCardAuth } from '@votingworks/auth';
+import { fakeLogger } from '@votingworks/logging';
+import { createMockUsbDrive } from '@votingworks/usb-drive';
+
+import { Store } from './store';
+import { buildApi } from './app';
+import { createWorkspace } from './util/workspace';
+
+const store = Store.memoryStore();
+const workspace = createWorkspace(tmp.dirSync().name, { store });
+const mockUsbDrive = createMockUsbDrive();
+
+afterAll(() => {
+  workspace.reset();
+});
+
+runUiStringApiTests({
+  api: buildApi(
+    buildMockInsertedSmartCardAuth(),
+    {
+      accept: jest.fn(),
+      return: jest.fn(),
+      scan: jest.fn(),
+      status: jest.fn(),
+      supportsUltrasonic: jest.fn(),
+    },
+    workspace,
+    mockUsbDrive.usbDrive,
+    fakeLogger()
+  ),
+  store: store.getUiStringsStore(),
+});
diff --git a/apps/scan/backend/src/store.ts b/apps/scan/backend/src/store.ts
index 122cd299cb..05ebd81003 100644
--- a/apps/scan/backend/src/store.ts
+++ b/apps/scan/backend/src/store.ts
@@ -32,7 +32,11 @@ import { sha256 } from 'js-sha256';
 import { DateTime } from 'luxon';
 import { join } from 'path';
 import { v4 as uuid } from 'uuid';
-import { ResultSheet } from '@votingworks/backend';
+import {
+  ResultSheet,
+  UiStringsStore,
+  createUiStringStore,
+} from '@votingworks/backend';
 import {
   clearCastVoteRecordHashes,
   getCastVoteRecordRootHash,
@@ -101,7 +105,10 @@ function resultSheetRowToResultSheet(row: ResultSheetRow): ResultSheet {
  * interpreted by reading the sheets.
  */
 export class Store {
-  private constructor(private readonly client: DbClient) {}
+  private constructor(
+    private readonly client: DbClient,
+    private readonly uiStringsStore: UiStringsStore
+  ) {}
 
   getDbPath(): string {
     return this.client.getDatabasePath();
@@ -119,14 +126,18 @@ export class Store {
    * Builds and returns a new store whose data is kept in memory.
    */
   static memoryStore(): Store {
-    return new Store(DbClient.memoryClient(SchemaPath));
+    const client = DbClient.memoryClient(SchemaPath);
+    const uiStringsStore = createUiStringStore(client);
+    return new Store(client, uiStringsStore);
   }
 
   /**
    * Builds and returns a new store at `dbPath`.
    */
   static fileStore(dbPath: string): Store {
-    return new Store(DbClient.fileClient(dbPath, SchemaPath));
+    const client = DbClient.fileClient(dbPath, SchemaPath);
+    const uiStringsStore = createUiStringStore(client);
+    return new Store(client, uiStringsStore);
   }
 
   // TODO(jonah): Make this the only way to access the store so that we always
@@ -572,7 +583,7 @@ export class Store {
     // Adding or deleting sheets would have updated the CVR count
     const { maxSheetsCreatedAt, maxSheetsDeletedAt } = this.client.one(`
         select
-          max(created_at) as maxSheetsCreatedAt, 
+          max(created_at) as maxSheetsCreatedAt,
           max(deleted_at) as maxSheetsDeletedAt
         from sheets
       `) as {
@@ -966,4 +977,8 @@ export class Store {
   clearCastVoteRecordHashes(): void {
     clearCastVoteRecordHashes(this.client);
   }
+
+  getUiStringsStore(): UiStringsStore {
+    return this.uiStringsStore;
+  }
 }
diff --git a/apps/scan/backend/src/util/workspace.ts b/apps/scan/backend/src/util/workspace.ts
index 1fcde64034..d186acb4fc 100644
--- a/apps/scan/backend/src/util/workspace.ts
+++ b/apps/scan/backend/src/util/workspace.ts
@@ -45,7 +45,10 @@ export interface Workspace {
   clearUploads(): void;
 }
 
-export function createWorkspace(root: string): Workspace {
+export function createWorkspace(
+  root: string,
+  options: { store?: Store } = {}
+): Workspace {
   const resolvedRoot = resolve(root);
   const ballotImagesPath = join(resolvedRoot, 'ballot-images');
   const scannedImagesPath = join(ballotImagesPath, 'scanned-images');
@@ -54,7 +57,7 @@ export function createWorkspace(root: string): Workspace {
   ensureDirSync(scannedImagesPath);
 
   const dbPath = join(resolvedRoot, 'ballots.db');
-  const store = Store.fileStore(dbPath);
+  const store = options.store || Store.fileStore(dbPath);
 
   return {
     path: resolvedRoot,
diff --git a/libs/backend/package.json b/libs/backend/package.json
index e7749beb00..e88a3340fd 100644
--- a/libs/backend/package.json
+++ b/libs/backend/package.json
@@ -36,6 +36,7 @@
   "dependencies": {
     "@votingworks/auth": "workspace:*",
     "@votingworks/basics": "workspace:*",
+    "@votingworks/db": "workspace:*",
     "@votingworks/fixtures": "workspace:*",
     "@votingworks/logging": "workspace:*",
     "@votingworks/types": "workspace:*",
diff --git a/libs/backend/src/index.ts b/libs/backend/src/index.ts
index c1a9a451b9..2571e6216c 100644
--- a/libs/backend/src/index.ts
+++ b/libs/backend/src/index.ts
@@ -7,3 +7,4 @@ export * from './list_directory';
 export * from './mock_usb';
 export * from './scan_globals';
 export * from './split';
+export * from './ui_strings';
diff --git a/libs/backend/src/ui_strings/index.ts b/libs/backend/src/ui_strings/index.ts
new file mode 100644
index 0000000000..9f876fe386
--- /dev/null
+++ b/libs/backend/src/ui_strings/index.ts
@@ -0,0 +1,4 @@
+/* istanbul ignore file */
+export * from './ui_strings_api';
+export * from './ui_strings_api_test_runner';
+export * from './ui_strings_store';
diff --git a/libs/backend/src/ui_strings/ui_strings_api.ts b/libs/backend/src/ui_strings/ui_strings_api.ts
new file mode 100644
index 0000000000..51322823cb
--- /dev/null
+++ b/libs/backend/src/ui_strings/ui_strings_api.ts
@@ -0,0 +1,55 @@
+/* istanbul ignore file - tested via VxSuite apps. */
+
+import { Optional } from '@votingworks/basics';
+import { Logger } from '@votingworks/logging';
+import {
+  Dictionary,
+  LanguageCode,
+  UiStringAudioKeys,
+  UiStringTranslations,
+  UiStringsApi,
+} from '@votingworks/types';
+
+import { UiStringsStore } from './ui_strings_store';
+
+/** App context for {@link UiStringsApi} endpoints. */
+export interface UiStringsApiContext {
+  logger: Logger;
+  store: UiStringsStore;
+}
+
+/** Creates a shareable implementation of {@link UiStringsApi}. */
+export function createUiStringsApi(context: UiStringsApiContext): UiStringsApi {
+  const { store } = context;
+
+  return {
+    getAvailableLanguages(): LanguageCode[] {
+      return store.getLanguages();
+    },
+
+    getUiStrings(input: {
+      languageCode: LanguageCode;
+    }): Optional<UiStringTranslations> {
+      throw new Error(
+        `Not yet implemented. Requested language code: ${input.languageCode}`
+      );
+    },
+
+    getUiStringAudioKeys(input: {
+      languageCode: LanguageCode;
+    }): Optional<UiStringAudioKeys> {
+      throw new Error(
+        `Not yet implemented. Requested language code: ${input.languageCode}`
+      );
+    },
+
+    getAudioClipsBase64(input: {
+      languageCode: LanguageCode;
+      audioKeys: string[];
+    }): Dictionary<string> {
+      throw new Error(
+        `Not yet implemented. Requested language code: ${input.languageCode} | audioKeys: ${input.audioKeys}`
+      );
+    },
+  };
+}
diff --git a/libs/backend/src/ui_strings/ui_strings_api_test_runner.ts b/libs/backend/src/ui_strings/ui_strings_api_test_runner.ts
new file mode 100644
index 0000000000..ee30f14bba
--- /dev/null
+++ b/libs/backend/src/ui_strings/ui_strings_api_test_runner.ts
@@ -0,0 +1,50 @@
+/* istanbul ignore file - test util */
+
+import { LanguageCode, UiStringsApi } from '@votingworks/types';
+import { UiStringsStore } from './ui_strings_store';
+
+/** Shared tests for the {@link UiStringsApi} and underlying store. */
+export function runUiStringApiTests(params: {
+  api: UiStringsApi;
+  store: UiStringsStore;
+}): void {
+  const { api, store } = params;
+
+  afterEach(() => {
+    jest.resetAllMocks();
+  });
+
+  test('getAvailableLanguages', () => {
+    expect(api.getAvailableLanguages()).toEqual([]);
+
+    store.addLanguage(LanguageCode.ENGLISH);
+    store.addLanguage(LanguageCode.ENGLISH); // Should be a no-op.
+    expect(api.getAvailableLanguages()).toEqual([LanguageCode.ENGLISH]);
+
+    store.addLanguage(LanguageCode.CHINESE);
+    expect([...api.getAvailableLanguages()].sort()).toEqual(
+      [LanguageCode.ENGLISH, LanguageCode.CHINESE].sort()
+    );
+  });
+
+  test('getUiStrings throws not-yet-implemented error', () => {
+    expect(() =>
+      api.getUiStrings({ languageCode: LanguageCode.SPANISH })
+    ).toThrow(/not yet implemented/i);
+  });
+
+  test('getUiStringAudioKeys throws not-yet-implemented error', () => {
+    expect(() =>
+      api.getUiStringAudioKeys({ languageCode: LanguageCode.CHINESE })
+    ).toThrow(/not yet implemented/i);
+  });
+
+  test('getAudioClipsBase64 throws not-yet-implemented error', () => {
+    expect(() =>
+      api.getAudioClipsBase64({
+        languageCode: LanguageCode.ENGLISH,
+        audioKeys: ['abc123', 'd1e2f3'],
+      })
+    ).toThrow(/not yet implemented/i);
+  });
+}
diff --git a/libs/backend/src/ui_strings/ui_strings_store.ts b/libs/backend/src/ui_strings/ui_strings_store.ts
new file mode 100644
index 0000000000..f609cd0ec8
--- /dev/null
+++ b/libs/backend/src/ui_strings/ui_strings_store.ts
@@ -0,0 +1,37 @@
+/* istanbul ignore file - tested via VxSuite apps. */
+
+import { Client as DbClient } from '@votingworks/db';
+import {
+  LanguageCode,
+  LanguageCodeSchema,
+  safeParse,
+} from '@votingworks/types';
+
+/** Store interface for UI String API endpoints. */
+export interface UiStringsStore {
+  // TODO(kofi): Fill out.
+  addLanguage(code: LanguageCode): void;
+  getLanguages(): LanguageCode[];
+}
+
+/** Creates a shareable implementation of the {@link UiStringsStore}. */
+export function createUiStringStore(dbClient: DbClient): UiStringsStore {
+  return {
+    addLanguage(languageCode: LanguageCode): void {
+      dbClient.run(
+        'insert or ignore into languages (code) values (?)',
+        languageCode
+      );
+    },
+
+    getLanguages(): LanguageCode[] {
+      const result = dbClient.all('select code from languages') as Array<{
+        code: string;
+      }>;
+
+      return result.map((row) =>
+        safeParse(LanguageCodeSchema, row.code).unsafeUnwrap()
+      );
+    },
+  };
+}
diff --git a/libs/types/src/index.ts b/libs/types/src/index.ts
index 0812e11ca8..bf1c2c4e45 100644
--- a/libs/types/src/index.ts
+++ b/libs/types/src/index.ts
@@ -18,6 +18,7 @@ export * from './generic';
 export * from './geometry';
 export * from './image';
 export * from './interpretation';
+export * from './language_code';
 export * from './numeric';
 export * from './polls';
 export * from './precinct_scanner';
@@ -29,5 +30,6 @@ export * from './tallies';
 export * from './ui_string_audio_clips';
 export * from './ui_string_audio_keys';
 export * from './ui_string_translations';
+export * from './ui_strings_api';
 export * from './ui_theme';
 export * from './voting_method';
diff --git a/libs/types/src/language_code.ts b/libs/types/src/language_code.ts
index f07f61134f..7820fd3502 100644
--- a/libs/types/src/language_code.ts
+++ b/libs/types/src/language_code.ts
@@ -1,6 +1,11 @@
+import { z } from 'zod';
+
 /* ISO 639-1 codes for supported VxSuite languages.  */
 export enum LanguageCode {
   CHINESE = 'zh',
   ENGLISH = 'en',
   SPANISH = 'es',
 }
+
+export const LanguageCodeSchema: z.ZodType<LanguageCode> =
+  z.nativeEnum(LanguageCode);
diff --git a/libs/types/src/ui_strings_api.ts b/libs/types/src/ui_strings_api.ts
new file mode 100644
index 0000000000..6e5fdbd09a
--- /dev/null
+++ b/libs/types/src/ui_strings_api.ts
@@ -0,0 +1,27 @@
+import { Optional } from '@votingworks/basics';
+
+import { Dictionary } from './generic';
+import { LanguageCode } from './language_code';
+import { UiStringAudioKeys } from './ui_string_audio_keys';
+import { UiStringTranslations } from './ui_string_translations';
+
+export interface UiStringsApi {
+  getAvailableLanguages(): LanguageCode[];
+
+  getUiStrings(input: {
+    languageCode: LanguageCode;
+  }): Optional<UiStringTranslations>;
+
+  getUiStringAudioKeys(input: {
+    languageCode: LanguageCode;
+  }): Optional<UiStringAudioKeys>;
+
+  /**
+   * Returns a map of the given audio keys to corresponding audio data in
+   * Base64-encoded byte format.
+   */
+  getAudioClipsBase64(input: {
+    languageCode: LanguageCode;
+    audioKeys: string[];
+  }): Dictionary<string>;
+}
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index d2565630f6..2b9916a477 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -2958,6 +2958,9 @@ importers:
       '@votingworks/basics':
         specifier: workspace:*
         version: link:../basics
+      '@votingworks/db':
+        specifier: workspace:*
+        version: link:../db
       '@votingworks/fixtures':
         specifier: workspace:*
         version: link:../fixtures