diff --git a/View/Requirements_Backend.php b/View/Requirements_Backend.php
index df4e4c21d..28a4fe6ce 100644
--- a/View/Requirements_Backend.php
+++ b/View/Requirements_Backend.php
@@ -931,43 +931,29 @@ class Requirements_Backend
 	 *                         'framework/javascript/lang'
 	 * @param bool $return Return all relative file paths rather than including them in
 	 *                         requirements
-	 * @param bool $langOnly Only include language files, not the base libraries
 	 *
 	 * @return array|null All relative files if $return is true, or null otherwise
 	 */
-	public function add_i18n_javascript($langDir, $return = false, $langOnly = false)
+	public function add_i18n_javascript($langDir, $return = false)
 	{
 		$files = array();
 		$base = Director::baseFolder() . '/';
-		if (i18n::config()->js_i18n) {
-			// Include i18n.js even if no languages are found.  The fact that
-			// add_i18n_javascript() was called indicates that the methods in
-			// here are needed.
-			if (!$langOnly) {
-				$files[] = FRAMEWORK_DIR . '/client/dist/js/i18n.js';
-			}
 
-			if (substr($langDir, -1) != '/') {
-				$langDir .= '/';
-			}
+		if (substr($langDir, -1) != '/') {
+			$langDir .= '/';
+		}
 
-			$candidates = array(
-				'en.js',
-				'en_US.js',
-				i18n::get_lang_from_locale(i18n::config()->default_locale) . '.js',
-				i18n::config()->default_locale . '.js',
-				i18n::get_lang_from_locale(i18n::get_locale()) . '.js',
-				i18n::get_locale() . '.js',
-			);
-			foreach ($candidates as $candidate) {
-				if (file_exists($base . DIRECTORY_SEPARATOR . $langDir . $candidate)) {
-					$files[] = $langDir . $candidate;
-				}
-			}
-		} else {
-			// Stub i18n implementation for when i18n is disabled.
-			if (!$langOnly) {
-				$files[] = FRAMEWORK_DIR . '/client/dist/js/i18nx.js';
+		$candidates = array(
+			'en.js',
+			'en_US.js',
+			i18n::get_lang_from_locale(i18n::config()->default_locale) . '.js',
+			i18n::config()->default_locale . '.js',
+			i18n::get_lang_from_locale(i18n::get_locale()) . '.js',
+			i18n::get_locale() . '.js',
+		);
+		foreach ($candidates as $candidate) {
+			if (file_exists($base . DIRECTORY_SEPARATOR . $langDir . $candidate)) {
+				$files[] = $langDir . $candidate;
 			}
 		}
 
diff --git a/admin/client/src/bundles/lib.js b/admin/client/src/bundles/lib.js
index de5730806..d93584260 100644
--- a/admin/client/src/bundles/lib.js
+++ b/admin/client/src/bundles/lib.js
@@ -21,7 +21,6 @@ require('expose?ReactAddonsTestUtils!react-addons-test-utils');
 require('expose?Page!page.js');
 require('expose?BootstrapCollapse!bootstrap/dist/js/umd/collapse.js');
 require('i18n.js');
-require('expose?i18nx!i18nx.js');
 
 require('babel-polyfill');
 require('../../../../thirdparty/jquery-ondemand/jquery.ondemand.js');
diff --git a/admin/client/src/i18nx.js b/admin/client/src/i18nx.js
deleted file mode 100644
index 2c962fd99..000000000
--- a/admin/client/src/i18nx.js
+++ /dev/null
@@ -1,55 +0,0 @@
-/**
- * Stub implementation for i18n code.
- * Use instead of framework/javascript/src/i18n.js
- * if you want to use any SilverStripe javascript
- * without internationalization support.
- */
-class i18nx {
-	constructor() {
-		this.currentLocale = 'en_US';
-		this.defaultLocale = 'en_US';
-	}
-
-	_t(entity, fallbackString, priority, context) {
-		return fallbackString;
-	}
-
-	sprintf(s, ...params) {
-		if (params.length === 0) {
-			return s;
-		}
-
-		const regx = new RegExp('(.?)(%s)', 'g');
-
-		let i = 0;
-
-		return s.replace(regx, function (match, subMatch1, subMatch2, offset, string) {
-			// skip %%s
-			if (subMatch1 === '%') {
-				return match; 
-			}
-
-			return subMatch1 + params[i += 1];
-		});
-	}
-
-	inject(s, map) {
-		const regx = new RegExp('\{([A-Za-z0-9_]*)\}', 'g');
-
-		return s.replace(regx, function (match, key, offset, string) {
-			return (map[key]) ? map[key] : match;
-		});
-	}
-
-	addDictionary() {
-
-	}
-
-	getDictionary() {
-
-	}
-};
-
-let _i18nx = new i18nx();
-
-export default _i18nx;
diff --git a/docs/en/04_Changelogs/4.0.0.md b/docs/en/04_Changelogs/4.0.0.md
index 600800e69..09ba1d997 100644
--- a/docs/en/04_Changelogs/4.0.0.md
+++ b/docs/en/04_Changelogs/4.0.0.md
@@ -144,6 +144,9 @@ If you have referenced these files elsewhere, please consider
 running the ES6 source files in `admin/client/src/legacy`
 through your own transpiling and bundle process.
 
+This also includes JavaScript i18n support, and the removal of the `i18n::js_i18n`
+configuration option used in `Requirements::add_i18n_javascript()`.
+
 SilverStripe core is moving away from `Requirements::combine_files` in favour of Webpack as of
 4.0. `Requirements::combine_files` is being considered for deprecation in future versions.
 
diff --git a/webpack.config.js b/webpack.config.js
index 41734ef60..e05733de1 100644
--- a/webpack.config.js
+++ b/webpack.config.js
@@ -68,7 +68,6 @@ const config = [
       'components/Toolbar/Toolbar': 'Toolbar',
       'deep-freeze-strict': 'DeepFreezeStrict',
       i18n: 'i18n',
-      i18nx: 'i18nx',
       jQuery: 'jQuery',
       'lib/Backend': 'Backend',
       'lib/ReducerRegister': 'ReducerRegister',