Can I ask Allah in Salat in Sujood of Dua in my own language? I don't know how to make Duas in Arabic. And one more thing: like this sujood, as you all may have heard of Salat Tawba. Can I perform the prayer every night as to ask Allah for forgiveness, even when I know I haven't done anything, just to repent to him, and to ask Allah for blessings through duas after in hope to make my duniya and aakhira successful?
If the worshipper can say du’aa’ well in Arabic, it is not permissible for him to make du’aa’ in any other language.
But if the worshipper is unable to make du’aa’ in Arabic, there is no reason why he should not make du’aa’ in his own language
Full fatwa: http://islamqa.info/en/20953
About the Tawba every night, you can do it.. And it's something good as in Quran 2:222 :
إِنَّ اللَّهَ يُحِبُّ التَّوَّابِينَ وَيُحِبُّ الْمُتَطَهِّرِينَ
"Indeed, Allah loves those who are constantly repentant and loves those who purify themselves."