diff --git a/src/bar.js b/src/bar.js
index 7e0868e..ee4f21b 100644
--- a/src/bar.js
+++ b/src/bar.js
@@ -195,10 +195,11 @@ export default class Bar {
     show_popup() {
         if (this.gantt.bar_being_dragged) return;
 
-        const start_date = date_utils.format(this.task._start, 'MMM D');
+        const start_date = date_utils.format(this.task._start, 'MMM D', this.gantt.options.language);
         const end_date = date_utils.format(
             date_utils.add(this.task._end, -1, 'second'),
-            'MMM D'
+            'MMM D',
+            this.gantt.options.language
         );
         const subtitle = start_date + ' - ' + end_date;
 
@@ -206,7 +207,7 @@ export default class Bar {
             target_element: this.$bar,
             title: this.task.name,
             subtitle: subtitle,
-            task: this.task
+            task: this.task,
         });
     }