Introduction to the semantics of questions.

Forty years of research has sought to determine whether nonhuman animals, like this bonobo, have a theory of mind.

An illustration from Becker and Tessier (2011) of a developmental U‐shape in Trevor's productions of KVT‐type words (e.g., “cat” and “kiss”). Ks and Ts represent the proportion of non‐faithful, harmonic tokens—for example, “cat” produced as “kak” (K) or “tat” (T)—per session; circles in the graph represent the proportion of faithful tokens—for example, “cat” produced as “cat.” The size of each symbol corresponds to the number of faithful or harmonized forms per session.