is an il word meaning “and then”, expressing something subsequent to something else. In the second sentence of the Babel text:
il ñatta jarēþa rūānnie il ñatta jamāesa japōññe sū jekiēn xīnār il aþ ñatta āke jamāramma;
it acts as part of a coordinating conjunction connecting the three clauses in the sentence. So:
they made a journey from the east
they found a plain in the land Shinar
they made there their home
While they journeyed from the east, they found a plain in the land of Shinar and made there their home.