What is the ruling on supplicating in English during prostration in obligatory prayers, and what is the ruling on supplicating with non-prescribed words of our own, whether in Arabic or other languages? Is it permissible to supplicate in any language?

It is permissible to supplicate in prayer in languages other than Arabic for one who is unable to speak Arabic. As for one who is able, it is not permissible for him to do so, except according to some jurists. It is permissible to supplicate with non-transmitted supplications, using any permissible words that do not contain sin. The essence of supplication is the presence of the heart and sincere recourse to Allah, in any language whatsoever.