Charity never faileth: but whether there be prophecies, they shall fail; whether there be tongues, they shall cease; whether there be knowledge, it shall vanish away. (1 Cor 13:8).
And when 1 Cor states that "where there be tongues, they shall cease", i believe it is saying that where there are languages spoken they will cease, or disappear. And you can admit that through time different people and their dialects have disappeared.