The function of timbre in 20th Century instrumental music is discussed in terms of the relation between timbre and musical language. Up to the 19th Century, the function of timbre was primarily related to its identity in addition to being charged with certain effective and symbolic characteristics. The identities of Western instruments are standardized, investing them with a certain neutrality that allows the construction of pitch hierarchies that are unperturbed by differences in timbre of the instruments. For small ensembles, timbre has a stability and a separating power that provides an identification and clarification of form and timbre. The function of timbral identity is one of articulation. With the modern orchestra, the use of instruments is more flexible and their identification becomes more mobile and temporary. Composing the blending of timbres into complex sound‐objects follows from the confronting of established sound hierarchies and an enriching of the sound vocabulary. The function of timbr...