The situation is the same with merit, I will not go into details, but it is much easier for Russian-speaking beginners to advance in rank than beginners who speak English or any other language.
The bottom line is local board only help members earn merit easier. Without local boards, they can discuss well in English, in international boards so to be honest, in most of cases, local boards are used not because of limitations in English.
I can bet that the average quality of posts that received merit would be lower than merited English posts.