Hi, apologies for the late response.

From what I can tell, Muhammad only spoke his local dialect of Arabic according to the consensus of scholars. However, there were significant Jewish and Christian communities in Arabia during Muhammad's lifetime, and interactions between Arabized Christians, Jews, and polytheistic/ pre-Islamic Arabs would have been commonplace and thus it is likely that Muhammad gained cultural knowledge of Abrahamic belief through either direct interaction between these peoples in the Arabic tongue or from another Arabic speaker who also knew either a biblical language like Hebrew, Aramaic, or Greek or spoke Syriac, a common language in the area that had a translation of the Bible. A Sunnah allegedly from Muhammad's scribe Zaid ibn Thabit also states that Muhammad asked him to learn Hebrew, which also could indicate that Muhammad wanted to have a translator for the language.

Sources: Muhammad, the Jews, and the Composition of the Qur’an: Sacred History and Counter-History (https://www.mdpi.com/2077-1444/10/1/63/htm)

A discussion about the version of the Bible available to Muhammad (http://www.scielo.org.za/scielo.php?script=sci_arttext&pid=S2305-08532017000200010)

Sunan Abi Dawud 3645 (https://sunnah.com/abudawud/26/5)