How many languages did prophet Muhammad (peace be upon him) know?
As far as human languages concerned, prophet Mohammad mother tongue was Arabic, He spoke language of Quraysh, people of Makkah. But He also knew other local Arabic dialects, and would communicate with visitors from other parts of Arabia in their own dialects.
On the other hand, His language was only vocal, he was unlettered, could not read or write. Which was explicitly noted in Qur'an chapter 29 (The Spider) verse 48:
(48) - وَمَا كُنْتَ تَتْلُو مِنْ قَبْلِهِ مِنْ كِتَابٍ وَلَا تَخُطُّهُ بِيَمِينِكَ ۖ إِذًا لَارْتَابَ الْمُبْطِلُونَ
“You ˹O Prophet˺ could not read any writing ˹even˺ before this ˹revelation˺, nor could you write at all. Otherwise, the people of falsehood would have been suspicious.”
Many Muslims ponder, on how could that be? Mohammad was a Prophet and must know all! Well this is not true!
Unfortunately some people exaggerate to an extreme extent by saying Mohammad could read and write in 70 languages, which is in complete contradiction with what Allah said in Qur'an.
There is a great wisdom behind this inability: anti Islam/Muslims insist that Prophet Mohammad copied the Quranic text and stories from the Bible. Well Makkah pagans at the time, called Mohammad all sort of names, but could not even accuse him of such, because they knew well , that he was only versed in Arabic, and that He was unlettered.
On other instances Prophet Mohammad, as was mentioned in Hadith, would communicate with animals and trees.