Hello please could you provide a screenshot to show which part of the interface you are referring to? You can use imgurl to share.
This problem is not resolved. I only added the image…
Do you wish to keep your site in French, but have WP-Optimize in English?
The plugin by default will display in the language you have set your site to unfortunately.
Where is the “language” file (e.g. “fr_FR.mo”)?
If I delete it (via FTP) then the plugin should switch back to its default English version…
It’s WordPress core, not individual plugins, that control overall language. Language files are in wp-content/languages. If you delete it and find that it comes back later, then this means WordPress core re-downloaded it (I’m not an expert on what conditions that happens under).
Looking at the code, I guess it is using WordPress language features, which explains the choice of the same language as the WordPress installation. I am not going to try to modify the code as it would create difficulties when updating…