CodingFabian

Because WPML creates posts and pages for each language, comments from one do not appear on the other. 
This plugin merges comments from all WPML translations of the posts and pages, so that they all are displayed on each other. 
Comments are internally still attached to the post or page they were made on.
It uses the <code>get_comments()</code> api call, which in some circumstances might not return all posts.

WPML comment merging

This plugin merges comments from all WPML translations of the posts and pages, so that they all are displayed on each other.

Nikolay Bachiyski

Sometimes we want the front end of our blog to be translated for the users, but keep the backend admin panel in English. Admin in English does just that.

Admin in English

Admin in English lets you have your administration panel in English, even if the rest of your blog is translated into another language.

WPML comment merging vs Admin in English