I think if the languages are very different (like for example Portuguese and Japanese) it would be less of a problem. But since Spanish has so many similarities those two are very tough ones to learn at the same time. When I started learning Portuguese for example, I could not speak a w whole sentence in French anymore, because I mixed them up way too much. Problably it helps if you are really advanced in one of the two first, and then start focusing on the second one. Otherwise it would be really confusing to me.

I think it’s a demanding and interesting situation. In my case, as I’m studying English and Spanish I believe I haven’t been having problems until now, and in fact sometimes I guess this situation can really help because some words make us remember others. However, sometimes I use to mix Portuguese (my mother tong) with Spanish, mainly when I don’t know the Spanish word. Here in Brazil, we use to call that “Portunhol”.

Acho que você pode aprender Espanhol e Português. Essas línguas são similares.