What is the hypothesis that language determines thought called?

The hypothesis that language determines thought is commonly called the Sapir–Whorf hypothesis. It is associated with American linguist Edward Sapir and his student Benjamin Lee Whorf, whose work encouraged debate about how the structure and vocabulary of a language may shape perception and reasoning.

The strongest version is known as linguistic determinism: it says that the language available to people determines, or severely limits, what they can think. A weaker and more widely discussed version, linguistic relativity, says that language influences habitual attention and interpretation without imprisoning thought. Modern research generally treats the weaker claim as more plausible than the extreme one.

The hypothesis is often illustrated through differences in color terms, spatial descriptions, grammatical gender, or how languages express time. However, it is misleading to say that speakers are incapable of understanding concepts their language does not encode with a single word. People can learn new concepts, translate ideas, and think beyond their native grammar. “Sapir–Whorf hypothesis” remains the standard popular label, even though Sapir and Whorf did not formulate one single formal hypothesis together.