Many Orthodox rabbis believe that the original language of mankind was Hebrew. Whether it was Hebrew or not, at one time there was only one language, which would have been the language spoken by Noah and family. Zephaniah 3:8-9 indicates that Hebrew might also be the language of all nations in the future. Hebrew is sometimes considered a “pure language” because there are no “cuss words” in it, only “cuss words” brought in from other languages.
In Genesis 11:1, we read, “And the whole earth was of one language, and of one speech.” The word used for “language” in this chapter isשֶׂפֶת (safat), which also means lip or shoreline. The more common word for “language” is lashon (לשון), which in Hebrew also means “tongue,” the organ that enables you to speak. And of course, it also means “language.” In Hebrew, when you say that someone speaks in tongues, it means that you are talking about someone who speaks more than one language.
In just a few generations after the Great Flood, we read that the people sought to build a tower in Shinar that would “reach into heaven.” God was very displeased with their efforts. This tower is commonly called “the tower of Babylon.” The Hebrew word for Babylon is Bavel, which means “confusion.” God said, “Come, let Us go down there and confuse their language, that they may not understand one another’s speech (Gen. 11:7).”
The Rabbis tell us that the kol was then split into seventy languages or “tongues.” Thereafter, the people scattered from Shinar in their new language groups to eventually populate the world. There are various tidbits of Hebrew which have filtered into various languages. For instance, the South Sea islanders had a high priest called the great kahuna (Hebrew for priesthood). They were also the original surfers. When surfing was brought to America, and the top surfer was called “the great kahuna.” The Hebrew word sak (שק) is sack in English. Other Hebrew words are in common usage in languages throughout the world.
When we come to Exodus 19:18-19, we read “And Mount Sinai was all in smoke, because YHWH descended upon it in fire, and the smoke thereof ascended as the smoke of a furnace, and the whole mount quaked greatly. 19And when the voice of the shofar sounded long, and waxed louder and louder, Moses spoke, and God answered him with kol.” The word kol is a Hebrew word, often translated as “thunder” or “voice.” According to much of Rabbinic Judaism, this “voice” broke up into all seventy of the languages of the ancient world. The “Ten Words (or Sayings),” from the Hebrew Aseret HaD’varim, are normally translated as “Ten Commandments (Exodus 34:28).” This means that the Ten Commandments were meant for the entire world. When God spoke these commandments in seventy different languages, He was speaking in “tongues.”
On Shavuot (Pentecost) about 1500 years later, a similar event happened, described in Acts chapter 2. The events described in this chapter happened at the Beit HaMikdash (Temple) in Jerusalem. This was the place of mikra kodesh (holy convocation) that Jews were commanded to go to on Shavuot, per Deuteronomy 16:16. Yeshua’s talmidim (disciples) remained observant Jews. “And they were all filled with the Ruach HaKodesh (Holy Spirit) and began to speak in other tongues as the Spirit was giving them utterance (Acts 2:4).” The words that they shared remains a mystery. However, I would assume that they were sharing the Good News of their beloved Messiah Yeshua.
“And there were dwelling at Jerusalem Jews, devout men, out of every nation under heaven. 6Now when this was noised abroad, the multitude came together, and were confounded, because every man heard them speak in his own language. 7And they were all amazed and marveled, saying one to another, ‘Behold, are not all these which speak Galileans?’ 8And how is it that we hear them in our own tongue, wherein we were born?”
Yeshua’s talmidim were supernaturally speaking the actual languages of Jews coming from many nations to Jerusalem for this very important pilgrimage festival. Just as the Ten Commandments were given in many different tongues, so too was the Gospel given in many tongues. They weren’t speaking in “unknown tongues,” but actual human languages. Then Shimon Kefa (Peter) shared the Good News quoting from the books of Joel and Psalms, totally from memory. Thousands of Jews believed the message that Peter gave. Three thousand were immersed that day (2:41). The Temple Mount was the only place where such mass immersions could take place, with its many mikveh baths located there.
 Curiously, God used a plural pronoun when referring to Himself, as in Genesis 1:26. This may be an expression of compound unity.