In order to prepare ourselves before the arrival of Jesus & Imam Mahdi (alayhuma salaam) we have to know the exact language they speak so we can communicate with them properly. Do they speak Arabic? what dialects of Arabic? or will Jesus speak Aramaic? or Hebrew? please clarify the details.
There's no specific answer to the question, so what's left is to guess based on what we know about those two figures.
The Mahdi [according to the Prophet] will be from the descendants of Fatima [RA]: https://sunnah.com/abudawud:4282
According to the Hadeeth, the Mahdi will be definitely an Arabic speaker, as he will start to dominate from Arabia.
On the other hand, we have Prophet Jesus [AS], and like Prophet Abraham [PBUH]; he was a multilingual speaker, he spoke:
- Aramaic, the language that was dominant among the Jews of Judea.
- Greek, the language of LXX Septuagint, which is the Torah translation Jesus studied before starting his ministry, see Qur'an [3:48].
- Hebrew to an extent.
Jesus didn't learn Arabic, unlike Prophet Abraham and Muhammad, but bear in mind that the Prophet spoke with Prophet Moses in the Night Journey without a translator, and Prophet Moses was originally an ancient Hebrew speaker, not Arabic.
So the only theory left is that Jesus will probably understand Arabic after the Second Coming, and not necessarily that he will need translators with him, a Messiah will certainly not have a language barrier as we do.
Allah knows the Truth.
Note: The name عيسي, and the word أنجيل, are arabized from Greek origin. The message Jesus preached in Judea must have been in the same language, yet we still are not certain whether that Injeel was a vocal message or written scripture. The Q document theory goes to point that this Injeel must have been the source of Matthew and Luke Gospels, which is why I believe that Jesus must have left a written scripture to the Disciples as we read in Mark 1:14-15 and Acts 8:25.
As Salaamu 3laykum,
I hope you are doing well. I believe there are no sources as to say what language they will speak. What has been narrated are the following:
- Jesus (Isa) Peace Be Upon Him on his physical description when he arrives
- Imam Mahdi physical description including his name and genealogy
ALLAH (Glory Be To HIM) Knows Best
Have a nice day!