We do not discriminate who is chosen and from what language. It is simply down to those who have consistently made high level quality reports on a consistent basis that have lead to many reports that were fixed and helped contribute to improving the game.
The active bug reports program is simply a yearly evaluation of all those who have contributed a lot to many bug reports. It is not a continuous payment or for only a few bug reports, but a high standard over a long period. It is our way of thanking those individuals and moving them a step closer to further options in future such as Technical Moderators should they continue contributing and wish to do so
This was all explained here: https://warthunder.com/en/news/6544-bug-reporting-active-reward-program-and-f-a-q-en