If Eri is the son of Gad and Gad is one of the twelve sons of Jacob and both eri and his father Gad were Jewish and they both lives in Egypt, how did eri formulated igbo language within some few years?

What makes him leave Egypt?

If Eri got married to two wives Nneamaku and Oboli and had 6 childrens, does it mean that there were people already living in Igbo land before Eri migrated because the women he married have igbo names before he came?

No offense, I just want to be cleared because something is quite not right here.