When chimpanzees or bonobos are learning aspects of human language, which component seems to be the barrier?

Question

Quizplus · Accepted Answer

Chimpanzees and bonobos have been shown to understand symbols, distinguish between different sounds, and learn vocabulary to some extent. However, using syntax, or the grammatical structure of language, has been more difficult for them to grasp. They may be able to learn individual words and phrases, but struggle to put them together in a way that follows the rules of language.

When Chimpanzees or Bonobos Are Learning Aspects of Human Language