This could be a bigger move than you might think. If Microsoft is going to present Mixer as an alternative to Twitch for gamers around the world, it arguably wants to court them in their native tongues. Twitch is already available in a slew of languages (including a few Microsoft doesn't have yet, like Greek and Vietnamese) and might be more alluring if your English skills aren't that great -- this helps level the playing field by making Mixer that much more accessible to a wide swath of the human population.