Every so often I get asked the question of whether Jesus (Yeshua) really spoke Hebrew (rather than Aramaic, Greek, or even Latin). After all, there seems to be some Aramaic words in the New Testament, and the text itself is written in Koine Greek.
First it must be stressed that this is not an "either Hebrew or Aramaic (or Greek)" question. It must be remembered that the region in which Jesus grew up was multicultural and multilingual. Under the Roman Empire, many Greek-speaking Gentiles lived around Nazareth, especially in the large city of Sepphoris. Jesus was able to speak with the Roman centurion (Matt. 8:5-13) and later with Pontius Pilate (John 18:28-38), but since it's unlikely that either of these Gentiles understood Aramaic, the conversation would mostly likely be held using Koine Greek (or perhaps Latin). So it's likely Jesus spoke Greek and even Latin.
And Jesus surely would have understood Aramaic, an ancient Syrian language that goes back to Aram (Gen. 10:23). Indeed, the descendants of Abraham's brother Nachor are called Arameans (Gen. 22:21) from whom Laban came. In Genesis 31:47 Jacob and Laban use different languages to describe a stone heap of witness (Laban used Aramaic but Jacob used Hebrew). Aramaic later became the language of the neighboring Assyria and was later adopted by many Jews during the time of the Babylonian Exile. Ezra the Scribe (4th century BC) wrote in Aramaic (as did the prophet Daniel), and later the Men of the Great Assembly established Aramaic script to be standardized for writing purposes. After the return of the exiles, Nehemiah later complained that assimilated Jews could no longer speak the Jew's native language -- i.e., Hebrew (Neh. 13:23-24).
Despite the encroachment of Aramaic, however, it must be remembered that Hebrew was regarded as Lashon Ha-Kodesh, the sacred language of the Jewish people, and the words of the Torah were sacrosanct. Hebrew was therefore regularly studied and preserved in the words of the Torah and various commentaries. And while it is true that Ezra standardized the Aramaic-style script for the Torah, the language itself was entirely Hebrew, and the script change was intended to separate the returning Jewish people from the Samaritan's who earlier had co-opted the Jewish Torah by means of Assyrian relocation policies. Ezra therefore established Torah reading (in Hebrew) every Sabbath for all synagogues and required Hebrew to be used in all Jewish rituals. He also established the Hebrew recitation of the Amidah (standing prayer) and other Jewish standards of practice. These policies were established hundreds of years before Jesus was born in Bet Lechem of the Galil (בֵּית לֶחֶם הַגְּלִילִית), and independent linguistic evidence indicates that Hebrew was used as a common language during the late second Temple period. For example, J.T. Milik wrote "Mishnaic [Hebrew] … was at that time the spoken dialect of the inhabitants of Judaea" (Ten Years of Discovery in the Wilderness of Judaea).
Undoubtedly Jesus was given a good Jewish education as a boy, even though he was born into a modest household. His family was devoutly Jewish, as indicated by their adherence to the Torah (Luke 2:39-42). He learned to read the Hebrew texts of the Bible and was adept at reasoning with the Torah sages of his day. At age 12, for example, we find him sitting in the Temple discussing the finer points of the Torah with the religious leaders of his day (Luke 2:39-52). Such a discussion undoubtedly occurred in Hebrew, not Aramaic (much less Greek or Latin).
During his public ministry, Jesus read the Hebrew Torah and Haftarah in synagogue "as was his custom" (Luke 4:16). Jesus also spoke about yod v'kotz shel yod - the Yod and it's stroke (i.e., "jots and tittles"), indicating the meticulous attention he gave to the written Hebrew Torah text (Matt. 5:18).
Jesus' first disciples were essentially uneducated men who spoke with a distinctive Galilean accent -- noted disparagingly in other literature as a corruption of the purer form of Hebrew spoken in Judea. Nonetheless, they attended synagogue with Jesus and lived Torah observant lifestyles.
Additional textual evidence that Jesus spoke Hebrew includes the fact that he spoke easily with the Samaritan woman at the well (the Samaritans preserved and spoke Hebrew, not Aramaic; John 4:4-26). The title over Jesus' cross was written "in Hebrew" (῾Εβραϊστί) not Aramaic as is sometimes erroneously translated (John 19:20). Jesus later spoke to the Apostle Paul in Hebrew (τῇ ῾Εβραΐδι διαλέκτω) on the Road to Damascus (Acts 26:14), and Paul gained the silence of the Jerusalem crowd by addressing them "in the Hebrew tongue" (Acts 21:40; Acts 22:2).
Unquestionably the Apostle Paul was fluent in Hebrew, since he was educated as a Pharisee in Jerusalem under the Rabbi Gamaliel (Acts 22:3), the grandson of the renowned Jewish sage Hillel the Elder. Paul described himself as circumcised on the eighth day, a Pharisee, and a "Hebrew of Hebrews" (Phil. 3:5). Rabbi Sha'ul (as he would have been called) was well-established in the Jewish leadership of his day, and even had a relationship with the Sanhedrin and High Priest of Israel (Acts 9:1-2). But even after his conversion on the road to Damascus (Acts 9:1-21), he still identified himself a Jew. In Acts 23:6 he confessed, "I am (not "was") a Pharisee." Paul also regularly attended synagogue: "He came to Thessalonica, where was a synagogue of the Jews. And Paul, as his manner was, went in unto them, and three Sabbath days reasoned with them out of the Scriptures" (Acts 17:1-2).
The Dead Sea Scrolls (DSS) of Qumran, known to date from the same general period, reveal an overwhelming preponderance of Hebrew texts. These include everything from commentaries to correspondence, from documents to daily rules. Scholars have discovered that all commentaries on the Scriptures were written in Hebrew -- none in Aramaic. The texts found at Herod's stronghold of Masada are written in Hebrew as well. The Talmud regularly distinguishes between Hebrew and other languages, especially Aramaic. For example, Tracate Sotah 49b states that either Hebrew or Greek should be used in Israel, but not Aramaic (the Zohar later picked this up and called Aramaic the "language of the evil force"). Sotah 33a and Shabbat 12b both state that "angels do not understand Aramaic." The historian Josephus also makes the distinction between Hebrew and Aramaic in his writings. And nearly all of the extant coins that date from the 4th century BC until the Bar Kochba Revolt (AD 135) are embossed in Hebrew (not Aramaic). Inscriptions on pottery vessels, tombs, and other items likewise attest that Hebrew was the spoken and written language of the common people. Simply put, Hebrew has always been the nationalistic language of the Jewish people.
In addition, many of the early "church fathers" also acknowledged that the statements of Jesus recorded in the gospels were in Hebrew. For example, Papias, a second century Church father, is quoted by the historian Eusebius: "Matthew collected the oracles in the Hebrew language, and each interpreted them as best he could" (Ecclesiastical History, III,39,1), and Iraneus (c. 200 AD) wrote: "Matthew issued a written Gospel among the Hebrews in their own dialect." Later, the famous translator Jerome wrote about a Hebrew Gospel he used to translate the Scriptures into Latin (De vir. ill., II). More recent scholarship by Dr. Robert Lindsey and others now indicates a Hebrew structure to the basic Greek New Testament (i.e., Hebrew syntax embedded within the Greek text). The thought patterns behind the New Testament are Hebraic -- not Aramaic or Greek. The scattered Aramaic words found in the New Testament are either loan words or are simply poorly transliterated Hebrew words and phrases rendered into Greek.
Jesus is called the very Word of God in John 1:1, a verse that mirrors the Hebrew text of Genesis 1:1. It is unthinkable that the promised Messiah, the King of the Jews in the lineage of Moses, King David and the Hebrew prophets, would have spoken His words of life using a foreign language to the Jewish people. As the King of the Jews, He would have spoken the language of the Jews.
Addendum: David Flusser's Statement:
The late Dr. David Flusser, Professor of Early Christianity and Judaism of the Second Temple Period at the Hebrew University of Jerusalem, states:
The spoken languages among the Jews of that period [at the time of Jesus] were Hebrew, Aramaic, and to an extent Greek. Until recently, it was believed by numerous scholars that the language spoken by Jesus' disciples was Aramaic. It is possible that Jesus did, from time to time, make use of the Aramaic language. But during that period Hebrew was both the daily language and the language of study. The Gospel of Mark contains a few Aramaic words, and this was what misled scholars. Today, after the discovery of the Hebrew Ben Sira (Ecclesiasticus), of the Dead Sea Scrolls, and of the Bar Kochba Letters, and in light of more profound studies of the language of the Jewish Sages, it is accepted that most people were fluent in Hebrew. The Pentateuch was translated into Aramaic for the benefit of the lower strata of the population. The parables in the Rabbinic literature, on the other hand, were delivered in Hebrew in all periods. There is thus no ground for assuming that Jesus did not speak Hebrew; and when we are told (Acts 21:40) that Paul spoke Hebrew, we should take this piece of information at face value.
This question of the spoken language is especially important for understanding the doctrines of Jesus. There are sayings of Jesus which can be rendered both in Hebrew and Aramaic; but there are some which can only be rendered into Hebrew, and none of them can be rendered only in Aramaic. One can thus demonstrate the Hebrew origins of the Gospels by retranslating them into Hebrew.
It appears that the earliest documents concerning Jesus were written works, taken down by his disciples after his death. Their language was early Rabbinic Hebrew with strong undercurrents of Biblical Hebrew. Even in [those books] of the New Testament which were originally composed in Greek, such as the Pauline Epistles, there are clear traces of the Hebrew language; and the terminology in those books of the New Testament which were composed in Greek is often intelligible only when we know the original Hebrew terms. In these books, we can trace the influence of the Greek translation of the Bible side by side with the influence of the Hebrew original. (Jewish Sources in Early Christianity, Adama Books)