Linguistic relativity

Linguistic relativity, also known as the Sapir-Whorf Hypothesis is a principle which suggests that the structure of a language effects the speaker's worldview or cognition. This theory was developed by linguists Edward Sapir and Benjamin Lee Whorf.

This is divided into two separate ideas, these being the Weak Sapir-Whorf Hypothesis and the Strong Sapir-Whorf Hypothesis, based upon the degree to which one believes it to take effect, with the latter being the source of much controversy.

Hopi Time Controversy
One of the most controversial applications of this theory, in particular to the strong variant of it, was in regards to time in the Hopi Language, in which Benjamin Lee Whorf argued that "no words, grammatical forms, construction or expressions that refer directly to what we call 'time'", and concluded that the Hopi had "no general notion or intuition of time as a smooth flowing continuum in which everything in the universe proceeds at equal rate, out of a future, through the present, into a past".

"I find it gratuitous to assume that a Hopi who knows only the Hopi language and the cultural ideas of his own society has the same notions, often supposed to be intuitions, of time and space as we have, and that are generally assumed to be universal. In particular he has no notion or intuition of time as a smooth flowing continuum in which everything in the universe proceeds at an equal rate, out of a future into a present and into a past .... After a long and careful analysis the Hopi language is seen to contain no words, grammatical forms, construction or expressions that refer directly to what we call 'time', or to past, present or future ..." Benjamin Lee Whorf

This conclusion was proven untrue by further study by other linguists, who through their research discovered the manner in which Hopi encodes time, describing it better as a form of Tenseless language which categorizes temporal relations through other means not seen in the Indo-European Languages that Whorf compared them to.