Collocation refers to a phrase or small group of words used together in normal speech with restrictions not explicitly imposed by grammar. Quite an odd concept, but vitally important to language learning. Correct use of collocation is probably the best way to identify a native speaker from a near native speaker.
I bring this up now because Julia made a wonderful example of an incorrect collocation for English. She came up with the phrase “two and a half hundred”. In English you can say “two and half thousand” and “two and half million” but for some reason it doesn’t work with hundreds (it does in Finnish incidentally).
Finnish, linguistics, collocation