QUICK REFERENCE (Source: Oxford Reference)

Broadly, the belief that people who speak different languages perceive and think about the world quite differently, their worldviews being shaped or determined by the language of their culture (a notion rejected by social determinists and by realists). The stance is loosely derived from the theories of Benjamin Lee Whorf and his teacher Edward Sapir in the 1930s, though subsequent interpretations often bear little relation to their actual claims. In its most extreme version the hypothesis can be described as relating two associated principles: linguistic determinism and linguistic relativism. While few linguists would accept the hypothesis in its strong, extreme, or deterministic form, many now accept a weak, more moderate, or limited Whorfianism, namely that the ways in which we see the world may be influenced to some extent by the kind of language we use. See also mould theory.

http://www.aber.ac.uk/media/Documents/short/whorf.html The Sapir-Whorf hypothesis

From:  Sapir-Whorf hypothesis  in  A Dictionary of Media and Communication »

Introduction

The Sapir-Whorf hypothesis (a.k.a. the Whorfian hypothesis) concerns the relationship between language and thought. Neither the anthropological linguist Edward Sapir (b. 1884–d. 1939) nor his student Benjamin Whorf (b. 1897–d. 1941) ever formally stated any single hypothesis about the influence of language on nonlinguistic cognition and perception. On the basis of their writings, however, two proposals emerged, generating decades of controversy among anthropologists, linguists, philosophers, and psychologists. According to the more radical proposal, linguistic determinism, the languages that people speak rigidly determine the way they perceive and understand the world. On the more moderate proposal, linguistic relativity, habits of using language influence habits of thinking. As a result, people who speak different languages think differently in predictable ways. During the latter half of the 20th century, the Sapir-Whorf hypothesis was widely regarded as false. Around the turn of the 21st century, however, experimental evidence reopened debate about the extent to which language shapes nonlinguistic cognition and perception. Scientific tests of linguistic determinism and linguistic relativity help to clarify what is universal in the human mind and what depends on the particulars of people’s physical and social experience.

General Overviews and Foundational Texts (Source: Oxford Bibliographies)

Writing on the relationship between language and thought predates Sapir and Whorf, and extends beyond the academy. The 19th-century German philosopher Wilhelm von Humboldt argued that language constrains people’s worldview, foreshadowing the idea of linguistic determinism later articulated in Sapir 1929 and Whorf 1956 (Humboldt 1988). The intuition that language radically determines thought has been explored in works of fiction such as Orwell’s dystopian fantasy 1984(Orwell 1949). Although there is little empirical support for radical linguistic determinism, more moderate forms of linguistic relativity continue to generate influential research, reviewed from an anthropologist’s perspective in Lucy 1997, from a psychologist’s perspective in Hunt and Agnoli 1991, and discussed from multidisciplinary perspectives in Gumperz and Levinson 1996 and Gentner and Goldin-Meadow 2003.

About the Sapir-Whorf Hypothesis:

Since its inception in the 1920s and 1930s, the Sapir-Whorf hypothesis has caused controversy and spawned research in a variety of disciplines including linguistics, psychology, philosophy, anthropology, and education.

                             
Edward Sapir and Benjamin Lee Whorf brought attention to the relationship between language, thought, and culture. Neither of them formally wrote the hypothesis nor supported it with empirical evidence, but through a thorough study of their writings about linguistics, researchers have found two main ideas.

a theory of linguistic determinism that states that the language you speak determines the way that you will interpret the world around you.
a weaker theory of linguistic relativism that states that language merely influences your thoughts about the real world.

Edward Sapir studied the research of Wilhelm von Humboldt. About one hundred years before Sapir published his linguistic theories, Humboldt wrote in Gesammelte Werke a strong version of linguistic determinism:

“Man lives in the world about him principally, indeed exclusively, as language presents it to him.”

Sapir took this idea and expanded on it. Although he did not always support this firm hypothesis, his writings state that there is clearly a connection between language and thought.

“Human beings do not live in the objective world alone, nor alone in the world of social activity as ordinarily understood, but are very much at the mercy of the particular language which has become the medium of expression in their society. It is quite an illusion to imagine that one adjusts to reality essentially without the use of language and that language is merely an incidental means of solving specific problems of communication or reflection: The fact of the matter is that the ‘real world’ is to a large extent unconsciously built up on the language habits of the group. No two languages are ever sufficiently similar to be considered as representing the same social reality. The worlds in which different societies live are distinct worlds, not merely the same world with different labels attached…Even comparatively simple acts of perception are very much more at the mercy of the social patterns called words than we might suppose…We see and hear and otherwise experience very largely as we do because the language habits of our community predispose certain choices of interpretation.

…from The Status of Linguistics as a Science (1929) Read more at the source.

The Linguistic Relativity Hypothesis (Stanford Encyclopedia of Philosophy)