Of course a marriage is valid as soon as it’s performed, but when is the marriage performed? In the eyes of modern, secular law, it’s performed when the witnesses sign the marriage certificate. But we’re not talking about modern, secular law.
I don’t know about Year 0 Jewish marriage law, but in the Catholic church, consummation is one step of marriage, and the marriage is not completely performed until consummated.
I have to think, for an account that was written so much much later, and which was then reinterpreted and retranslated again and again over the centuries, that the word has greater significance than that. “Firstborn” implies that there was a second- and maybe even a third- or more-borns after that.
He would have written in Aramaic or Greek. Hebrew wasn’t commonly spoken then, it was an ancient ritual language. The related language, Aramaic, was the cradle-tongue of most of the Hebrews, but Greek was the language of commerce, and widely spoken.
Hebrew and Aramaic are different languages. There is one common prayer in the Jewish liturgy in Aramaic, and it sounds really different from all the other ones that are in Hebrew. I knew it sounded different as a kid, before I learned that it was a different language.
The Hebrew word in Isaiah is best translated into English as “young woman”. And that’s how it is translated in the Jewish Publication Society’s translation, which is based on the Hebrew (without reference to the Greek and Latin texts) and done by a team of biblical scholars.
But yes, the Septuagint (the accepted contemporary Greek translation of the Bible) used the word “virgin” or “maiden”, and that’s no-doubt the source of confusion, as Greek was commonly spoken at the time, and Hebrew wasn’t. So most Hebrews at the time of Jesus were more familiar with the Septuagint than with the original. And I assume that’s why the people who wrote the gospels cared whether Mary was a virgin.
As far as I know, intercourse still IS one of the three legitimate ways for Jews to be married, the others being a bride price (such as the wedding ring) or a contract. We like to include all three, but any one is (still, among modern Jews) considered valid.
So I see no reason to doubt that Joseph was Mary’s husband. Of course, it’s a little awkward that he wasn’t Jesus’s FATHER, but hey…