There are so many. Where and when did it happen?
The gift of language did not originate with humans, language was given to us by our Creator. He gave the first human, Adam, the ability not only to speak but also to coin new words and expand his vocabulary. Genesis 2:19, 20
Genesis 2:23 Then man said: " This is at last bone of my bones and flesh of my flesh. This one will be called Woman, Because from man she was taken."
Language is a part of every living thing's life, expressed through different means. More complex animals like cats use their tails, eyes, voices, and more to talk to other animals. It may not be a language of words, but it's still a language. Humans, being the most complex animal in nature, developed a complex form of language which we call words: combining different sounds for different meanings, eventually turning into a verbal human language.
Everybody makes up words just because they need to convey information to other people. Pidgin is a language of made-up words, some made from English, some made from French, and some invented out of the air. What is the sound of a knife? Everybody knows knives go "chook", so the pidgin word for knife is chook. Americans like beef, so all animals are beef. Porcupine? Chook chook beef. The plural of any word is simply the word twice.
More examples: www.youtube.com/watch?v=sQPYkdp_7Vc