Best way to learn language?

What's the best way to learn a new language also without forgetting the others?

I know a bit of french Spanish I would like to learn them both fully also a few other languages too but when I tried to learn french Spanish for some reason I kept...

forgetting how to speak in English lol!
Why is that? :S

Thanks!

I have the same problem.
When I was a child my parents only taught me Vietnamese.

And so when I entered school, I learned english and completely forgot how to speak viet. I'm regaining that ability through my parents though.

Because since they know that I can't speak Vietnamese very well, they only speak that in the house, so it's either learn or don't understand for my case.

Maybe your parents could help? Lame, but mine did.

RosettaStone Program

The only reason you'd forget a language is because you arent speaking it enough... my parents know 7 languages and can speak them all (I unfortunately can only understand those languages), so it is possible, it just means you have to practice them all...

Rosetta Stone by far the best way.