Linguistic Variability and Intellectual Development, Wilhelm von Humbolt’s most famous work, was published by his brother Alexander posthumously, in 1836. It promptly established itself as a classic in the philosophy of language and has held that position ever since. With many examples from a vast multitude of languages, from Sanskrit to Delaware Indian, the author shows how character and structure of a language expresses the inner life and knowledge of its speakers and how their intellectual development is in turn shaped by their language.