The principle of linguistic relativity is Benjamin Whorf's theory of the way in which an individual's thoughts are influenced by the language(s) they have available to express them.
Many versions of this theory have been proposed and debated, some under the name of the Sapir-Whorf hypothesis and sometimes just as Whorf's hypothesis or the Whorfian hypothesis. Whorf himself objected strongly to the latter two names, maintaining that he had made many other hypotheses, and that if this particular theory was being attributed to him then surely he had the right to name it.
Although Whorf spoke of his theory as being that thoughts were "determined" by the language available to express them, it is doubtful that he intended this in the sense of determinism as the term is understood in philosophy or psychology.
Apart from the controversy over whether it is valid, the principle of linguistic relativity has resulted in concrete applications outside of linguistics. Douglas Engelbart was inspired by the principle, among other ideas, to invent a variety of things like hypertext, the graphical user interface, and the mouse.