In what language did the Prophet (blessings and peace of Allah be upon him) lead the other prophets in prayer during the Isra’ (Night Journey)?
Question

In which language muhammad lead the other Prophets in prayer in al-Masjid al-Aqsa?
Praise be to Allah.There is no text which states the language in which the Prophet (blessings and peace of Allah be upon him) spoke with his fellow prophets on the night of the Isra’ and Mi‘raj. This matter is not something with which the Muslim should concern himself, because no actions result from knowing that. But if the Isra’ and Mi‘raj, and the gathering of all the prophets to pray together in al-Masjid al-Aqsa, was a great miracle, then their coming together to pray in a single language cannot be any greater or more miraculous than that. However, what appears to be the case is that the language that the Prophet (blessings and peace of Allah be upon him) spoke with the other prophets on the night of the Isra’ and Mi‘raj was Arabic, because this is the language of the Prophet (blessings and peace of Allah be upon him) and the language of his people, and there is no report to indicate that the Prophet (blessings and peace of Allah be upon him) spoke with anyone or called anyone to Islam in any language other than his own, which was Arabic. If the Prophet (blessings and peace of Allah be upon him) had spoken to them in any other language, the people would surely have paid attention to it and narrated it.
Moreover, if it had been essential for them to speak one language, and for him to address them all in that language, then his eloquent Arabic language was the most appropriate language for that, because he is the one who spoke it, and in it his Book was revealed, in addition to what is affirmed about the superiority of Arabic over all other languages. It is sufficient to note that it is the language of the last of the divine messages and the greatest of the divinely-revealed books.
For more information, please see the answer to question no. 161844 .
With regard to the Prophet (blessings and peace of Allah be upon him) leading the other prophets in prayer in al-Masjid al-Aqsa on that blessed night, his prayer was also in Arabic, we think, for the reasons we have mentioned above, and because the Qur’an was revealed in Arabic. Allah, may He be exalted, says (interpretation of the meaning):
{Indeed, We have made it an Arabic Qur’an} [az-Zukhruf 43:3]
{Indeed, We have sent it down as an Arabic Qur’an } [Yoosuf 12:2]
{In a clear Arabic language} [ash-Shu‘ara’ 26:195].
Because the Qur’an is a miracle in its words and meanings, if it is changed then it loses its unique style, so it is no longer Qur’an and it is not even like it; rather it has become an explanation or commentary on it, and if its explanation were like it, they would not be unable to match it and it would not have challenged them to produce a surah like it.
Hence the majority of jurists are of the opinion that it is obligatory to recite Qur’an in Arabic in the prayer, and that recitation is only valid if it is done in Arabic.
An-Nawawi said in al-Majmu‘ (3/379): Our view is that it is not permissible to recite the Qur’an in any language except Arabic, whether the individual is able to recite in Arabic or not, and whether that is in prayer or otherwise. If he recites a translation in the prayer instead of reciting the Arabic text, his prayer is not valid, regardless of whether or not he is able to recite. This is our view and the view of the majority of scholars, including Malik, Ahmad and Dawud. End quote.
Furthermore, Abu Hanifah originally said that it is valid for one who is able to recite in Arabic in the prayer to recite in another language, then he recanted and adopted the view of his two companions, and stipulated that in order for the prayer to be valid (if offered in another language), the individual should be unable to recite in Arabic.
Al-Marghinani said in al-Hidayah fi Sharh Bidayat al-Mubtadi (1/49): It is narrated that he recanted and adopted concerning that issue the view of his two companions, and that is the correct view. End quote.
In Hashiyat Ibn ‘Abidin (1/484), Ibn ‘Abidin confirmed the soundness of the report which says that he recanted [his earlier view].
Hence az-Zarqani said in Manahil al-‘Irfan (2/163): The leading scholars are unanimously agreed that it is not permissible to recite the Qur’an in any language other than Arabic outside of prayer, and the one who wants to do that must be sternly prevented from doing so, because reciting it in any other language would lead to reciting Qur’an in a manner that does not reflect its miraculous nature; rather it would sound very inarticulate. As for reciting it in a language other than Arabic in prayer, that is haram according to scholarly consensus, for the reason mentioned above. End quote.
And Allah knows best.