As much as I love languages, I’ve always limited myself to learning ONE or TWO at a time. I’m not sure I admire people who say they are learning six languages at the same time. Mostly, I’m just skeptical of them.
Personally, I think it’s okay to learn multiple languages at the same time if you’re definitely at different levels in each language. For me, my Korean isn’t impeccable or anything but my Korean abilities >>>>>>> my Japanese abilities. Now, when I learn new things in Japanese, I liken them to things I already knew in Korean and that actually helps me learn better. It also helps that Japanese and Korean have quite a bit of similarities, both in terms of vocabulary, SOME general grammar constructions (though I find that most Japanese grammar is quite different from Korean grammar), and even some expressions. So studying Japanese sometimes helps me reinforce what I already know in Korean; at least, it forces me to think, “Hm. Is there an equivalent expression in Korean?” or “How would I express this in Korean?” I think it might actually be helpful to learn two somewhat related or linguistically similar languages at the same time rather than learning just one or two completely unrelated languages. That way, if you get exhausted or frustrated studying one language, you can switch to the other one but still somewhat unconsciously be reviewing the other one. Does that even make sense? Haha. At least, that’s the kind of relationship I have with Japanese and Korean. Also, once you’re quite comfortable with one language, you could use that language to learn another linguistically similar one. For example, learning Japanese using Korean (or vice versa) is probably an infinity times easier than learning either one from English, just because English is SO different from Japanese and Korean. (But, of course, you’d probably want to stick to using English to learn languages French or Spanish, rather than any East Asian language.)
But suppose you’re learning like two NEW (zero-experience) languages at the same time. If they’re completely unrelated to each other, personally, I feel that you’d be doing a disservice to yourself. You’d hinder your progress in BOTH languages. It may take you longer to digest different sets of vocabulary and completely different grammar points. And I feel that the time that you divide between two languages (specifically if you’re at the zero-experience, BEGINNER level in both) could be better spent in progressing faster in ONE language. Once you reach a certain degree of comfort in one language, I think it’ll be worth starting a new one. That way, like I said, if you ever get tired of one, you could take a break and study the other, even if the languages are unrelated. On the other hand, if you’re starting from ground zero in two “similar” languages – like Hindi and Marathi or Korean and Japanese, again, I think you’d be at a disadvantage. It’s possible you could easily get mixed up and hinder your progress in both.
Honestly, I’m VERY skeptical of people who say they’re learning Korean, Japanese, Vietnamese, Thai, French, Spanish, etc. etc. all at the same time. I just don’t think it’s a fruitful way to become proficient in ANY language. But that’s just my opinion. What do you guys think? (*SOB* Not that anyone leaves me any comments anymore…)