This is the conclusion of linguists. Linguists’ definition of language necessarily includes a productive grammar. It’s not enough to be capable of uttering from

This is the conclusion of linguists. Linguists’ definition of language necessarily includes a productive grammar. It’s not enough to be capable of uttering from a long list of sounds or signs. To have language we must be able to regularly construct novel and unique communications composed of strings of symbols governed by grammatical rules. All animals that we’ve studied — including great apes we’ve attempted to teach sign language — have so far failed to demonstrate the acquisition of grammar. This means the number of unique communications they can express is exactly limited to the number of utterances they know.