There’s an old cliché in linguistics that a language is a dialect with an army and navy behind it. This isn’t merely a joke. Defining when a new language is born is than defining when a caterpillar becomes a butterfly. In the process by which a dialect becomes a language there is no easy empirical equivalent of the point when the butterfly emerges from the larva able to take off. So no linguist can look back and say: “That’s it, Wednesday 5 May 1213, that’s when the English language finally got wingss.”

GLOSSARY
caterpillar – lagarta