Coach and Streak in Different Languages

[AndresC.]

I am beginning to learn Italian and would like to try the coach system.

Question: If I activate the coach while in Italian, will I lose my German streak also and get it replaced by a coach there too?

Or can you have coaches for some languages and streaks for others in the same account?

Thanks.

[BastouXII]

What's a coach ? How does it work ?

I also want to know if a streak is dependent on language (i.e. if I practice one out of two languages, do I loose my streak for the other one) ?