Index: src/wp-admin/css/login.css
===================================================================
--- src/wp-admin/css/login.css	(revision 51938)
+++ src/wp-admin/css/login.css	(working copy)
@@ -281,7 +281,7 @@
 
 #login {
 	width: 320px;
-	padding: 8% 0 0;
+	padding: 5% 0 0;
 	margin: auto;
 }
 
@@ -409,10 +409,41 @@
 	display: none;
 }
 
+#language-switcher {
+	padding: 0;
+	overflow: visible;
+	background: none;
+	border: none;
+	box-shadow: none;
+}
+
+#language-switcher select {
+	height: 30px;
+	margin-right: 0.5em;
+}
+
+.language-switcher {
+	margin: 0 auto 24px;
+	text-align: center;
+}
+
+.language-switcher label {
+	margin-right: 0.5em;
+}
+
+.login .language-switcher .button-primary {
+	float: none;
+	margin-bottom: 0;
+}
+
 @media screen and (max-height: 550px) {
 	#login {
 		padding: 20px 0;
 	}
+
+	#language-switcher {
+		margin-top: 0;
+	}
 }
 
 
@@ -428,3 +459,10 @@
 		margin: -0.1875rem 0 0 -0.25rem;
 	}
 }
+
+@media screen and (max-width: 400px) {
+	.login .language-switcher .button-primary {
+		display: block;
+		margin: 5px auto 0;
+	}
+}
Index: src/wp-includes/l10n.php
===================================================================
--- src/wp-includes/l10n.php	(revision 51938)
+++ src/wp-includes/l10n.php	(working copy)
@@ -144,10 +144,18 @@
 		$determined_locale = get_user_locale();
 	}
 
-	if ( ! empty( $_GET['wp_lang'] ) && ! empty( $GLOBALS['pagenow'] ) && 'wp-login.php' === $GLOBALS['pagenow'] ) {
-		$determined_locale = sanitize_text_field( $_GET['wp_lang'] );
+	$wp_lang = '';
+
+	if ( ! empty( $_GET['wp_lang'] ) ) {
+		$wp_lang = $_GET['wp_lang'];
+	} elseif ( ! empty( $_COOKIE['wp_lang'] ) ) {
+		$wp_lang = $_COOKIE['wp_lang'];
 	}
 
+	if ( ! empty( $wp_lang ) && ! empty( $GLOBALS['pagenow'] ) && 'wp-login.php' === $GLOBALS['pagenow'] ) {
+		$determined_locale = sanitize_text_field( $wp_lang );
+	}
+
 	/**
 	 * Filters the locale for the current request.
 	 *
@@ -1480,6 +1488,7 @@
  * @since 4.3.0 Introduced the `echo` argument.
  * @since 4.7.0 Introduced the `show_option_site_default` argument.
  * @since 5.1.0 Introduced the `show_option_en_us` argument.
+ * @since 5.9.0 Introduced the `explicit_option_en_us` argument.
  *
  * @see get_available_languages()
  * @see wp_get_available_translations()
@@ -1499,6 +1508,8 @@
  *     @type bool     $show_available_translations  Whether to show available translations. Default true.
  *     @type bool     $show_option_site_default     Whether to show an option to fall back to the site's locale. Default false.
  *     @type bool     $show_option_en_us            Whether to show an option for English (United States). Default true.
+ *     @type bool     $explicit_option_en_us        Whether the English (United States) option uses an explict value of en_US
+ *                                                  instead of an empty value. Default false.
  * }
  * @return string HTML dropdown list of languages.
  */
@@ -1516,6 +1527,7 @@
 			'show_available_translations' => true,
 			'show_option_site_default'    => false,
 			'show_option_en_us'           => true,
+			'explicit_option_en_us'       => false,
 		)
 	);
 
@@ -1525,7 +1537,7 @@
 	}
 
 	// English (United States) uses an empty string for the value attribute.
-	if ( 'en_US' === $parsed_args['selected'] ) {
+	if ( 'en_US' === $parsed_args['selected'] && ! $parsed_args['explicit_option_en_us'] ) {
 		$parsed_args['selected'] = '';
 	}
 
@@ -1580,8 +1592,10 @@
 	}
 
 	if ( $parsed_args['show_option_en_us'] ) {
+		$value = ( $parsed_args['explicit_option_en_us'] ) ? 'en_US' : '';
 		$structure[] = sprintf(
-			'<option value="" lang="en" data-installed="1"%s>English (United States)</option>',
+			'<option value="%s" lang="en" data-installed="1"%s>English (United States)</option>',
+			esc_attr( $value ),
 			selected( '', $parsed_args['selected'], false )
 		);
 	}
Index: src/wp-login.php
===================================================================
--- src/wp-login.php	(revision 51938)
+++ src/wp-login.php	(working copy)
@@ -207,6 +207,59 @@
 	?>
 	<div id="login">
 		<h1><a  target="_top" href="/newspapers?url=<?php echo esc_url( $login_header_url ); ?>"><?php echo $login_header_text; ?></a></h1>
+
+		<?php
+		$languages = get_available_languages();
+
+		if ( ! empty( $languages ) && ! $interim_login ) { ?>
+
+		<div class="language-switcher">
+			<form id="language-switcher" action="" method="get">
+
+				<label for="language-switcher-locales">
+					<span class="dashicons dashicons-translation" aria-hidden="true"></span>
+					<span class="screen-reader-text"><?php _e( 'Language' ); ?></span>
+				</label>
+
+				<?php
+					$args = array(
+						'id'                          => 'language-switcher-locales',
+						'name'                        => 'wp_lang',
+						'selected'                    => determine_locale(),
+						'show_available_translations' => false,
+						'explicit_option_en_us'       => true,
+						'languages'                   => $languages,
+					);
+
+					/**
+					 * Filters default arguments for the Languages dropdown on the login screen.
+					 *
+					 * @since 5.9.0
+					 *
+					 * @param Array $args Arguments for the Languages dropdown on the login screen.
+					 */
+					wp_dropdown_languages( apply_filters( 'wp_login_language_switcher_args', $args ) );
+				?>
+
+				<?php if ( $interim_login ) { ?>
+					<input type="hidden" name="interim-login" value="1" />
+				<?php } ?>
+
+				<?php if ( isset( $_GET['redirect_to'] ) && '' !== $_GET['redirect_to'] ) { ?>
+					<input type="hidden" name="redirect_to" value="<?php echo esc_url_raw( $_GET['redirect_to'] ) ?>" />
+				<?php } ?>
+
+				<?php if ( isset( $_GET['action'] ) && '' !== $_GET['action'] ) { ?>
+					<input type="hidden" name="action" value="<?php echo sanitize_text_field( $_GET['action'] ) ?>" />
+				<?php } ?>
+
+					<input type="submit" class="button button-primary" value="<?php _e( 'Change' ); ?>">
+
+				</form>
+			</div>
+
+	<?php } ?>
+
 	<?php
 	/**
 	 * Filters the message to display above the login form.
@@ -419,6 +472,10 @@
 	setcookie( TEST_COOKIE, 'WP Cookie check', 0, SITECOOKIEPATH, COOKIE_DOMAIN, $secure );
 }
 
+if ( isset( $_GET['wp_lang'] ) ) {
+	setcookie( 'wp_lang', $_GET['wp_lang'], 0, COOKIEPATH, COOKIE_DOMAIN, $secure );
+}
+
 /**
  * Fires when the login form is initialized.
  *