I am currently in the process of learning both French and Arabic. At the same time. This is a task that is actually way harder than I thought it would be. Lots of things go very wrong a lot of the time. Here are five of the most difficult aspects of learning your second and third languages at the same time:
1. Vocabulary mix ups.
I was sitting with my sister trying to go through some French flash cards to review for my class the next day. Since we have both taken some of the language, I figured she could help with this basic vocab in case I couldn't remember. I was filing through, saying the English word aloud, then saying the Arabic, then getting frustrated, then saying the French. It was a whole kerfuffle.
2. Translation errors.
This one really bugs. I was translating my Arabic homework to English and after I finish this huge paragraph, I go back in and read it to make sure it makes sense and there were several words written in French. I had to rewrite the stupid thing becuase of course, I did it in pen....
3. Grammatical Errors.
Some languages have similar grammer rules. Arabic and French for example, often switch the adjective and the noun around. Because of this sometimes when I am trying to use the grammer rules they get mixed up because they are similar, but not the same.
4. Wait, what's the word?
Lots of people find this hilarious, not me. Not unlike vocabulary mix ups, sometimes I forget the word I am looking for in every language. So there I sit, gesturing like an idiot trying to mime the word because all three of my languages have failed me...
5. Conversing with people who only speak one of the two.
Now this was the most difficult thing I have ever done, ever. We have a lady in our mosque who speaks a little English and French. Most everyone else speaks some English and Arabic. Well, the lady who speaks French was trying to talk to the lady who speaks Arabic and they pulled me right in the middle. I am nowhere near fluent in either language, but I can understand a lot of French, and a little Arabic. So as I was trying to translate through the three languages I began speaking French to the lady who spoke Arabic, and Arabic to the lady who spoke French. It was a mess. I am a mess.
I highly recommend learning as many languages as you can get your hands on. Just not at the same time, for sanities sake....