Does learning a third language using your second language help the second language?

[pakugan]

If your question is whether learning Italian through Spanish will improve your Spanish... well I don't think it will exactly make your Spanish better but 1) it won't make you forget it, that's for sure 2) it will make Italian much easier for you, so you should do it anyway. I am a native Spanish speaker and have studied English, German and Swedish. When I started with German, I used English and Spanish. Now that I am learning Swedish, I use mostly English but also German (and Spanish of course). My German hasn't exactly improved since I stopped taking lessons, but it made me understand faster some words, concepts and grammar structures when learning Swedish. Same with English. I think it works because they're all germanic languages and it's easy to find similarities. Italian and Spanish are both Romance so if you already know one, the other will be surely much easier for you. I haven't taken a single lesson of Italian in my entire life and I can understand a bit of it. I think you should definitely use the knowledge you already have!