To a child, "you follow me" and "me follow you" communicate different ideas. a chimpanzee well trained in sign language might use the same sequence of signs for both phrases because it is incapable of

Because it is incapable of "Appropriate syntax".

Syntax is the manner by which words and accentuation are utilized and arranged to shape expressions, provisos and sentences. This can mean the choice of a word or the word's strained, the course of action of the words and the choice of the punctuation. 
Syntax is otherwise called the investigation of the principles that must be taken after to make very much framed expressions, statements and sentences.