diff --git a/wp-admin/admin-header.php b/wp-admin/admin-header.php
index 8f2023830..95951ed29 100644
--- a/wp-admin/admin-header.php
+++ b/wp-admin/admin-header.php
@@ -43,7 +43,8 @@ var userSettings = {
 	pagenow = '<?php echo $current_screen->id; ?>',
 	typenow = '<?php if ( isset($current_screen->post_type) ) echo $current_screen->post_type; ?>',
 	adminpage = '<?php echo $admin_body_class; ?>',
-	thousandsSeparator = '<?php echo addslashes( $wp_locale->number_format['thousands_sep'] ); ?>';
+	thousandsSeparator = '<?php echo addslashes( $wp_locale->number_format['thousands_sep'] ); ?>',
+	decimalPoint = '<?php echo addslashes( $wp_locale->number_format['decimal_point'] ); ?>';
 //]]>
 </script>
 <?php
diff --git a/wp-includes/functions.php b/wp-includes/functions.php
index 27b5477de..b6c90fd73 100644
--- a/wp-includes/functions.php
+++ b/wp-includes/functions.php
@@ -131,14 +131,13 @@ function date_i18n( $dateformatstring, $unixtimestamp = false, $gmt = false ) {
  * @since 2.3.0
  *
  * @param int $number The number to convert based on locale.
- * @param int $decimals Precision of the number of decimal places. Deprectated.
+ * @param int $decimals Precision of the number of decimal places.
  * @return string Converted number in string format.
  */
-function number_format_i18n( $number, $decimals = null ) {
+function number_format_i18n( $number, $decimals = 0 ) {
 	global $wp_locale;
 	$number = (int)$number;
-	if ( !is_null( $decimals ) ) _deprecated_argument( __FUNCTION__, '3.0' );
-	$formatted = number_format( $number, 0, null, $wp_locale->number_format['thousands_sep'] );
+	$formatted = number_format( $number, absint( $decimals ), $wp_locale->number_format['decimal_point'], $wp_locale->number_format['thousands_sep'] );
 	return apply_filters( 'number_format_i18n', $formatted );
 }
 
@@ -163,7 +162,7 @@ function number_format_i18n( $number, $decimals = null ) {
  * @param int $decimals Precision of number of decimal places. Deprecated.
  * @return bool|string False on failure. Number string on success.
  */
-function size_format( $bytes, $decimals = null ) {
+function size_format( $bytes, $decimals = 0 ) {
 	$quant = array(
 		// ========================= Origin ====
 		'TB' => 1099511627776,  // pow( 1024, 4)
@@ -172,10 +171,9 @@ function size_format( $bytes, $decimals = null ) {
 		'kB' => 1024,           // pow( 1024, 1)
 		'B ' => 1,              // pow( 1024, 0)
 	);
-	if ( !is_null( $decimals ) ) _deprecated_argument( __FUNCTION__, '3.0' );
 	foreach ( $quant as $unit => $mag )
 		if ( doubleval($bytes) >= $mag )
-			return number_format_i18n( round( $bytes / $mag ) ) . ' ' . $unit;
+			return number_format_i18n( $bytes / $mag, $decimals ) . ' ' . $unit;
 
 	return false;
 }
diff --git a/wp-includes/load.php b/wp-includes/load.php
index b765a896e..e46b9de60 100644
--- a/wp-includes/load.php
+++ b/wp-includes/load.php
@@ -219,7 +219,7 @@ function timer_stop( $display = 0, $precision = 3 ) { // if called like timer_st
 	$mtime = explode( ' ', $mtime );
 	$timeend = $mtime[1] + $mtime[0];
 	$timetotal = $timeend - $timestart;
-	$r = number_format( $timetotal, $precision );
+	$r = ( function_exists( 'number_format_i18n' ) ) ? number_format_i18n( $timetotal, $precision ) : number_format( $timetotal, $precision );
 	if ( $display )
 		echo $r;
 	return $r;
diff --git a/wp-includes/locale.php b/wp-includes/locale.php
index 882e9395d..4972b8b7d 100644
--- a/wp-includes/locale.php
+++ b/wp-includes/locale.php
@@ -181,6 +181,10 @@ class WP_Locale {
 		/* translators: $thousands_sep argument for http://php.net/number_format, default is , */
 		$trans = __('number_format_thousands_sep');
 		$this->number_format['thousands_sep'] = ('number_format_thousands_sep' == $trans) ? ',' : $trans;
+		
+		/* translators: $dec_point argument for http://php.net/number_format, default is . */
+		$trans = __('number_format_decimal_point');
+		$this->number_format['decimal_point'] = ('number_format_decimal_point' == $trans) ? '.' : $trans;
 
 		// Import global locale vars set during inclusion of $locale.php.
 		foreach ( (array) $this->locale_vars as $var ) {