At that time I will change (or restore) the
speech of the peoples
to a pure speech,
that all of them may call on the
name of the LORD
and serve him with one accord.
Compare with (Isaiah 6:5) "...for I (am) a man of unclean lips, and I live among a people of unclean lips ..."
a man compare with peoples
unclean compare with pure or clear
lips compare with a ... speech
lip in Hebrew also means speech, language
HalleluJah! Praise the Lord!