It’s depend on your theme’s translation.
I just changed to other language, such as Japanese, it still has the same issue.
I also tried to change coment-template. Still not work.
What need I to do?
Find the .mo and .po files in your theme folder, and learn to how to edit with poedit.
Read the code, and find the real coment-template which works. Replace the code like this:
<?php __('theme_name','Leave A Comment');?>
I installed Simple Chinese version, and most of words on UI have been translated to Simaple chinese, but parts of words are not translated. Such as comments related.
Following link is a sample.
It is still show English words “Leave a Comment”, “Post Comment”.