Conversation so far:
Did Maurice Merleau-Ponty create art?
Merleau-Ponty distinguishes between primary and secondary modes of expression.
What are the distinctions between them?
sometimes repeated in terms of spoken and speaking language.
What is repeated?
distinguishes between primary and secondary modes of expression.
What are these modes of expression?
CANNOTANSWER.
Are there any other interesting aspects about this article?
It is speaking language, that is to say, primary expression, that interests Merleau-Ponty.
Is his art usually based on language and speaking?
"Indirect Language and the Voices of Silence.

Question: What is his most well-known contribution to the art world?
Self-contained rewrite: What is Maurice Merleau-Ponty's most well-known contribution to the art world?