On the evolutionary history of 'yes' and 'no'

Small words like ‘yes’ and ‘no’ play an important part in our daily communication, but do we clearly know where they come from? Their origin is rather mysterious. We do not know if we need these words at all, since some languages manage without them. For instance, speakers of Celtic languages answer affirmatively and negatively by repeating verbs. However, functional motivations to have ‘yes’ and ‘no’ are obvious, since they are economical, and even those languages without obvious ‘yes’ and ‘no’ terms tend to form some sort of informational verbal signs corresponding to them. Our hypothesis is that in an initial stage ‘no’ is derived from a negation marker, and then becomes an independent word. Since the negative answer can be given with ‘no’, its affirmative counterpart is required. A number of features in linguistic structures are organized in binary pairs, and this is one such case. By revealing the history of ‘yes’ and ‘no’, one can detect one aspect of cognitive evolution in human communication, in a sense that the ever-growing demands for effective communication forced speakers to invent a new tactic based on a binary opposition to allow smoother communication.