What language did Jesus speak?

Jesus probably spoke three languages: Aramaic, Hebrew and Greek.

Aramaic

The common language of Galilee during the time of Jesus was Aramaic. It was an ancient Semitic language related to Hebrew. Although Jews had spoken Hebrew as their main language up to the time of the captivity, Aramaic became the dominant language after the captivity. Consequently, it was probably Jesus’ first or native language.

There are several places in the gospels where Jesus’ words are given in Aramaic: Raca (Matthew 5:22, “Empty head”); Talitha kum (Mark 5:41, “Little girl, get up!”); Ephphatha (Mark 7:34, “Be opened”); Abba (Mark 14:36. “Father”); Eloi, Eloi, lema sabachtani? (Matthew 27:46 & Mark 15:34, “My God, my God, why have you forsaken me?”).

Most people think that Jesus primarily taught in Aramaic.

Hebrew

Most (but not all) scholars believe that, by the time of Jesus, not many Jews could speak or read Hebrew. Only scholars learned Hebrew in order to read the Old Testament in its original language. However, it seems likely that Jesus knew Hebrew because he read from the law in the synagogue (Luke 4:16-21).

A small number of scholars believe that Hebrew was still widely used in Jesus’ time, especially for rabbinical teaching, and that Jesus possibly taught in Hebrew as well.

Greek

Greek was the lingua franca of the Roman world — much like English is in today’s world. When communicating with someone who didn’t speak your native language, it was common to use Greek because most people knew some Greek. Galilee was known to be a multi-lingual area with many Greek-speaking Gentiles living near Nazareth. In fact, it is called “Galilee of the Gentiles (Matthew 4:15), perhaps because of its multi-cultural character. Only a few miles from Nazareth was the large Roman city of Sepphoris and it is very likely that Jesus spent some time working there, and therefore he must have known enough Greek to get by, and possibly knew it fluently.

There are examples in the New Testament of Jesus speaking with people who probably did not know Aramaic or Hebrew. For example, the Roman centurion (Matthew 8:5-13; Luke 7:2-10; John 4:46-53), Pontius Pilate (Mark 15:2–5; Matthew 27:11–14; Luke 23:3; John 18:33-38), the Syro-Phoenician woman (Mark 7:25-30). There are also the Greeks who came to speak to him in John 12:20-22. In all these cases, Jesus probably spoke to them in Greek.

References

1. Aramaic of Jesus (Wikipedia)
2. Fitzmyer, J.A. (1992) Did Jesus speak Greek? Biblical Archaeology Review, 18(4).
3. Roberts, M.D. (2004) What language(s) did Jesus speak and why does it matter?