I don't know exactly which one of the two Mari languages:
It's Meadow Mari.
It is quite hard to tell the difference, the title would perhaps be the same in both languages (ош = white, висвис = daisy?) but I found the lyrics here
and there are some words that would differ slightly in Hill Mari, like уло, 'is' (Hill Mari улы), гай, 'as' (Hill Mari гань), чыла, 'everything' (Hill Mari цила) etc.
It sounds like a candidate for the Forum Song Contest ...