Merleau-Ponty distinguishes between primary and secondary modes of expression. This distinction appears in Phenomenology of Perception (p. 207, 2nd note [Fr. ed.]) and is sometimes repeated in terms of spoken and speaking language (le langage parle et le langage parlant) (The Prose of the World, p. 10). Spoken language (le langage parle), or secondary expression, returns to our linguistic baggage, to the cultural heritage that we have acquired, as well as the brute mass of relationships between signs and significations. Speaking language (le langage parlant), or primary expression, such as it is, is language in the production of a sense, language at the advent of a thought, at the moment where it makes itself an advent of sense.  It is speaking language, that is to say, primary expression, that interests Merleau-Ponty and which keeps his attention through his treatment of the nature of production and the reception of expressions, a subject which also overlaps with an analysis of action, of intentionality, of perception, as well as the links between freedom and external conditions.  The notion of style occupies an important place in "Indirect Language and the Voices of Silence". In spite of certain similarities with Andre Malraux, Merleau-Ponty distinguishes himself from Malraux in respect to three conceptions of style, the last of which is employed in Malraux's The Voices of Silence. Merleau-Ponty remarks that in this work "style" is sometimes used by Malraux in a highly subjective sense, understood as a projection of the artist's individuality. Sometimes it is used, on the contrary, in a very metaphysical sense (in Merleau-Ponty's opinion, a mystical sense), in which style is connected with a conception of an "uber-artist" expressing "the Spirit of Painting". Finally, it sometimes is reduced to simply designating a categorization of an artistic school or movement. (However, this account of Malraux's notion of style--a key element in his thinking--is open to serious question.)  For Merleau-Ponty, it is these uses of the notion of style that lead Malraux to postulate a cleavage between the objectivity of Italian Renaissance painting and the subjectivity of painting in his own time, a conclusion that Merleau-Ponty disputes. According to Merleau-Ponty, it is important to consider the heart of this problematic, by recognizing that style is first of all a demand owed to the primacy of perception, which also implies taking into consideration the dimensions of historicity and intersubjectivity. (However, Merleau-Ponty's reading of Malraux has been questioned in a recent major study of Malraux's theory of art which argues that Merleau-Ponty seriously misunderstood Malraux.) For Merleau-Ponty, style is born of the interaction between two or more fields of being. Rather than being exclusive to individual human consciousness, consciousness is born of the pre-conscious style of the world, of Nature.

Answer this question "What is his most well-known contribution to the art world?" by extracting the answer from the text above.
Malraux to postulate a cleavage between the objectivity of Italian Renaissance painting