That's the best part about being born, unlike just quantum leaping into a situation people forgive your lack of understanding and gladly teach you. However, should you be born a Japanese girl with full knowledge of your past life one should avoid speaking their own language as questions WILL be asked... These are all just hypotheticals of course...

you know, I never hear about the japanese struggling with their language. granted, I don't speak japanese either so I wouldn't know if they were.

I refuse to believe anyone can actually read Japanese. I can speak a very little bit of Japanese but I have no idea about the language at all. I don't know how to approach a language that lacks the concept of an alphabet.

How to Japanese people know how to write a particular word? In most languages you can hear the word and at least get a good idea of how it's written, even if it's a made-up word. In manga there are a lot of made up, in universe words, and I do not understand how they decide how to write to write to them down or how anyone who reads those words knows how to pronounce the word.