"Sign language apes" may not be as accurate a term as "Apes that have been taught some signs." Certainly, chimps and gorillas have, under instruction, learned to utilise signs to covey simple desires or feelings, but there has not been a majority consensus amongst linguists and cognitive scientists that the brief symbol strings displayed by the apes constitute a syntax, which is required for communication to qualify as full-blown language. "bad-frown-sad" is an expression of emotion but it is not a sentence.
Interesting stuff all the same, and worthy of further research.



