diff --git a/bin/update-readmes.js b/bin/update-readmes.js
index f57bca0a0e089..cd79242c8615c 100755
--- a/bin/update-readmes.js
+++ b/bin/update-readmes.js
@@ -22,7 +22,7 @@ const packages = [
 	'element',
 	'escape-html',
 	'html-entities',
-	//'i18n',
+	'i18n',
 	'keycodes',
 	//'plugins',
 	//'priority-queue',
diff --git a/packages/i18n/README.md b/packages/i18n/README.md
index 5e57b0f4cb806..6779e866f2453 100644
--- a/packages/i18n/README.md
+++ b/packages/i18n/README.md
@@ -2,7 +2,7 @@
 
 Internationalization utilities for client-side localization.
 
-https://codex.wordpress.org/I18n_for_WordPress_Developers
+<https://codex.wordpress.org/I18n_for_WordPress_Developers>
 
 ## Installation
 
@@ -37,38 +37,129 @@ npx pot-to-php languages/myplugin.pot languages/myplugin-translations.php text-d
 
 ## API
 
-`__( text: string, domain: string ): string`
+<!-- START TOKEN(Autogenerated API docs) -->
 
-Retrieve the translation of text.
+### setLocaleData
+
+[src/index.js#L45-L58](src/index.js#L45-L58)
+
+Merges locale data into the Tannin instance by domain. Accepts data in a
+Jed-formatted JSON object shape.
+
+**Related**
+
+-   <http://messageformat.github.io/Jed/>
+
+**Parameters**
+
+-   **data** `?Object`: Locale data configuration.
+-   **domain** `?string`: Domain for which configuration applies.
+
+### sprintf
+
+[src/index.js#L159-L167](src/index.js#L159-L167)
+
+Returns a formatted string. If an error occurs in applying the format, the
+original format string is returned.
+
+**Related**
+
+-   <http://www.diveintojavascript.com/projects/javascript-sprintf>
+
+**Parameters**
+
+-   **format** `string`: The format of the string to generate.
+-   **args** `...string`: Arguments to apply to the format.
+
+**Returns**
+
+`string`: The formatted string.
+
+### \_n
+
+[src/index.js#L125-L127](src/index.js#L125-L127)
+
+Translates and retrieves the singular or plural form based on the supplied
+number.
+
+**Related**
 
-See: https://developer.wordpress.org/reference/functions/__/
+-   <https://developer.wordpress.org/reference/functions/_n/>
 
-`_x( text: string, context: string, domain: string ): string`
+**Parameters**
+
+-   **single** `string`: The text to be used if the number is singular.
+-   **plural** `string`: The text to be used if the number is plural.
+-   **number** `number`: The number to compare against to use either the singular or plural form.
+-   **domain** `?string`: Domain to retrieve the translated text.
+
+**Returns**
+
+`string`: The translated singular or plural form.
+
+### \_nx
+
+[src/index.js#L144-L146](src/index.js#L144-L146)
+
+Translates and retrieves the singular or plural form based on the supplied
+number, with gettext context.
+
+**Related**
+
+-   <https://developer.wordpress.org/reference/functions/_nx/>
+
+**Parameters**
+
+-   **single** `string`: The text to be used if the number is singular.
+-   **plural** `string`: The text to be used if the number is plural.
+-   **number** `number`: The number to compare against to use either the singular or plural form.
+-   **context** `string`: Context information for the translators.
+-   **domain** `?string`: Domain to retrieve the translated text.
+
+**Returns**
+
+`string`: The translated singular or plural form.
+
+### \_x
+
+[src/index.js#L107-L109](src/index.js#L107-L109)
 
 Retrieve translated string with gettext context.
 
-See: https://developer.wordpress.org/reference/functions/_x/
+**Related**
+
+-   <https://developer.wordpress.org/reference/functions/_x/>
 
-`_n( single: string, plural: string, number: Number, domain: string ): string`
+**Parameters**
 
-Translates and retrieves the singular or plural form based on the supplied number.
+-   **text** `string`: Text to translate.
+-   **context** `string`: Context information for the translators.
+-   **domain** `?string`: Domain to retrieve the translated text.
 
-See: https://developer.wordpress.org/reference/functions/_n/
+**Returns**
+
+`string`: Translated context string without pipe.
+
+### \_\_
+
+[src/index.js#L92-L94](src/index.js#L92-L94)
+
+Retrieve the translation of text.
 
-`_nx( single: string, plural: string, number: Number, context: string, domain: string ): string`
+**Related**
 
-Translates and retrieves the singular or plural form based on the supplied number, with gettext context.
+-   <https://developer.wordpress.org/reference/functions/__/>
 
-See: https://developer.wordpress.org/reference/functions/_nx/
+**Parameters**
 
-`sprintf( format: string, ...args: mixed[] ): string`
+-   **text** `string`: Text to translate.
+-   **domain** `?string`: Domain to retrieve the translated text.
 
-Returns a formatted string.
+**Returns**
 
-See: http://www.diveintojavascript.com/projects/javascript-sprintf
+`string`: Translated text.
 
-`setLocaleData( data: Object, domain: string )`
 
-Creates a new Jed instance with specified locale data configuration.
+<!-- END TOKEN(Autogenerated API docs) -->
 
 <br/><br/><p align="center"><img src="https://s.w.org/style/images/codeispoetry.png?1" alt="Code is Poetry." /></p>
diff --git a/packages/i18n/src/index.js b/packages/i18n/src/index.js
index 42266da0c9ff9..50869f49efd39 100644
--- a/packages/i18n/src/index.js
+++ b/packages/i18n/src/index.js
@@ -150,7 +150,7 @@ export function _nx( single, plural, number, context, domain ) {
  * original format string is returned.
  *
  * @param {string}   format  The format of the string to generate.
- * @param {string[]} ...args Arguments to apply to the format.
+ * @param {...string} args Arguments to apply to the format.
  *
  * @see http://www.diveintojavascript.com/projects/javascript-sprintf
  *