[magnusjonsson]

When I started learning Mandarin (my fourth language) I became totally unable to speak French (my third language) as the Mandarin words would pop up first in my mind. I think by now they've been sufficiently separated in my mind but I haven't had any use for my French so it as atrophied anyway. I'm now learning Cantonese which is similar to Mandarin and I'm only occasionally mixing it up with Mandarin. It seems to me the distance between languages isn't so important, you can mix up any two languages or not. It probably depends more on how much your brain has to rewire itself to acconmmodate the new language?