I think that is a linguistic question ultimately. You could take potentially utter a new sentence never before uttered even with the top 10 most used words in a language.
That is one of the most significant things about the human being. Actually I am quite surprised when people come with definitions for human nature eg. fundamentally good, fundamentally evil, homo sapiens, homo faber, etc. that the linguistic potential to turn a small set of things into infinity is often ignored. No other animal can think and speak like we do.
Fair point but I think then it just expands the consideration from linguistic (which is already more than spoken or written, it also covers signed, whistled, drummed, danced, in one case I heard about – eye movement) to semiotic.