Plugin translations problem

Question

I developed a plugin for my client in english by default. I created estonian and russian translation files. But my client installed wordpress with estonian language by default and now, when my plugin is activated it doesn't use estonian translation file, because I guess wordpress uses estonian language by default. Russian language works well.
Client uses qtranslate-x plugin for translations. What should I do to solve this problem?

Answer 1

I am not confident without downloading Estonian copy of WP source, but from look at GlotPress it seems that locale code for it is simply et, not et_EE.