（？）Who wants to find a language partner? So, we need to add a subject，I 

(我)要找到语言交换朋友

你要不要跟我一起很认真得读书？

(If you want to keep "de", I think it should be 地, which is using to desicribe verb）

I think by doing thisway, it looks more native.

Hope it helps you. 

By the way, I really like Korean Drama. :)

我要找到一起学语言的朋友

你要不要跟我一起认真得读书？

我要找到语言交换朋友

你要不要跟我一起很认真地读书（学习语言）？