Your friend perhaps was telling you about Aramaic, influenced by Mel Gibson's movie "The Passion of the Christ"? Any way, his mistake is that he identifies the language spoken by Jesus and his first disciples with the language of the New Testament. Aramaic was indeed used where Jesus lived and taught, but the language of the New Testament is Greek. How is that possible?
As you know Jews crucified Christ. The Christian church may have started in Israel, but it was denied in Israel. The first Christians were Greeks or Greek-speaking, and wherever Christianity was spreading, even in Rome, it was spreading among Greeks or Greek speaking populations. In Rome the pagans used to call Christians "Greeks", because it was the Greeks that were becoming Christians. You can read on this a detailed essay by D. Constantelos, Greek Orthodoxy - From Apostolic Times to the Present Day
Since the old Christian church was Greek, the members of this Church, whether they were living in Rome, or in Athens, or in Corinth, or in Thessaloniki, etc., they needed texts written in Greek, in order to think about and understand their faith. Notice the Epistles of Paul. They are addressed all to Greek communities, whether in mainland Greece or elsewhere. Even the Epistle to the Romans is written in Greek, because the Christian community in Rome was Greek.
Some of the texts circulating among the first Christians acquired in the course of time a special esteem for their value and importance. These texts formed the Canon of the New Testament, i.e. the New Testament as we know it today.
This final text, the Canon, was transmitted from generation to generation until now. The New Testament is not kept in a museum. The text that we use today in Greek speaking Churches, is the text that comes from the old Christian communities.