Dan,
The prophecy in Isaiah 7 is twofold. There was a sign given of a young virgin who would have gotten married and had a son whom they named Immanuel which means God with us (Isa.8:8-10). The Jews knew God spoke in types and similitudes and shadows.
But since the scriptures are about Christ who was to come, as with most prophecies (the testimony of Jesus is the spirit of prophecy-Rev.19:10) there is a view of a literal and more significant understanding. The Holy Ghost had revealed to the Jews that there would be a "seed of the woman" Gen.3:15. He proceeded further to show them he would come through Judah (Gen.49:10). He showed David he would come from his loins but he would be the son of God. This is another example of a prophecy which has Solomon and Jesus Christ in view. See 1 Chronicles 17:11-14, and 2 Samuel 7:12-16. Jesus was the son of David but God was his father. How would God be to him a father- he would be conceived by a virgin. It would be in Bethlehem that this would happen but he would have no beginning of days (Heb.7:3) but would be "from everlasting"- Micah 5:2
Isaiah further revealed that this son who is conceived in a virgin would be called Wonderful, Counselor, the Mighty God the everlasting Father and the Prince of Peace (9:6) This is why his name was called Immanuel- God with us (7:14).