If I don't speak Arabic and I want to make Du'aa while I am in prayers. For example, in Tahajud while the prostration is long Can I make Du'aa in my language until I learn Arabic.
Yes, it is permissible to make du’aa’ in a language other than Arabic, if one does not speak it. But the Muslim has to learn enough Arabic to do the acts of worship properly. And Allaah knows best.