Re: "Jesus, almost certainly spoke in Aramaic or Hebrew. The Gospel was probably recorded in one of those languages first, and then translated to the Greek definitive version. Also the Greek of that time cannot be understood perfectly by any linguist without knowing the culture of that time. "
The first known "book" of the New Testament was compiled no earlier than 60 years after the crucifixion of Jesus, by "second generation" followers who put to letters "word of mouth" recollections. It is believed to be written in Damascus, and is known to us today as The Gospel of Mark. Much of what became "Church Dogma" - the virgin birth stories and "The Annunciation by the Angel Gabriel" offered in later texts, is not mentioned at all in this first book. All of the New Testament writings were written in the Greek language by people born into Greek culture and living in a world surrounded with numerous Greek Mystery Cults found throughout the ancient world, as well as the Cult of Mithraism which was heavily practiced in the Roman World. Central in most of these cults was a gnostic mythos: "The Queen of Heaven" gives virgin birth to a god-man who imparts sacred and secret knowledge to his selected followers, and then he willingly sacrifices his life, rises from the dead, and lives forever in the abode of the gods, having fulfilled his role as savior of the world. It was not until the Third Century C.E. at the Council of Nicea held by the Emperor Constantine that the Church leaders decided which writings were to be considered "official, unquestionable" Christian texts which became the New Testament. The exact authorship of most of these works is unknown, even though attributed to one or another of Jesus' disciples. All of the remaining texts which offered views about Jesus in opposition to the Church leaders were banned and burned, along with all of their followers and believers. Thus came to be the official New Testament - a Greek book teaching Greek culture, full of inconsistencies and hypocrisies, which condemns all Jews as the enemy of G-d, and teaches that the One Indivisible Omniscient and Omnipotent Creator G-d of the Universe is now divided into Three Separate G-d Divisions - The Father, The Son, and The Holy Spirit. Mary is now The Queen of Heaven. Belief in her virgin born son is the gnosis - the salvation through acceptance of secret knowledge imparted by the g=d-man sacrificing hero, and any and all Torah doctrines are deemed Satanic heresies in denial of The Son's "New Covenant" - one in which only faith that Jesus is both equal to G-d and also faith that Jesus is also G-d's own son by the Virgin Queen of Heaven is required for salvation. It's doctrines further state that the true Covenant People, the Jews, are eternally condemned and to be considered an 'extinct race', in the future to be replaced by all who renounce Judaism and accept the god-man story.
In short: Christianity as we know it today is little more than a rewriting of ancient Greek Gnostic Mystery Cults and the renaming of ancient pagan gods. Its followers had no knowledge of Jews or Torah and had long been worshipping and praying to the Divine Virgin Mother of Heaven and her Son. Their prayers included the saying the Rosary (almost identical in prose and prayer to the Catholic version today), self-flagellation (again practiced by Catholics today), and many other rites and rituals taken directly from pagan religions of the time. As the Church spread, The Roman Feast of Saturnalia was deemed Christmas day, and the Celtic sex/fertility rites of Spring were deemed to be Easter Sunday. Even the sun worshipper's sacred day "Sun-Day" was declared to be the official Christian Sabbath "Sunday". While it is a fact that the people to first follow Jesus and believe that he was the Jewish Messiah were Jews from ancient Israel, they, along with anyone else who disagreed with the Council of Nicea, were declared heretics, rooted out, executed, and their books burned.
Thus began the early Christian Church, which further evolved and expanded over the next 1700 years into the bewildering forms we see today everywhere in the world.