Cognitive semantics refers to a way of approaching linguistics that deals with the way the mind processes language in relationship to its meaning, or conceptual content, within a given context. Unlike traditional approaches to linguistics, cognitive semantics cannot be easily broken down into branches of study such as phonetics, syntax, etc., because it sees all of these as interrelated to meaning. Cognitive linguists also reject the notion that linguistic processing is a specialized function that can be separated from other mental processes.
Before the advent of cognitive semantics in the 1970s, approaches to linguistics could generally be divided into psychological and formal approaches. Psychological approaches focus on the relationship between language and other psychological phenomena, such as reasoning and memory. Formal approaches tend to address specifically grammar-related aspects of linguistics, sometimes treating meaning as a separate issue altogether. Cognitive semantics, however, tries to unify the two methods by asserting that both fall under the umbrella of semantics.
In general, semantics refers to the branch of linguistics that deals with how language conveys meaning. It is closely related to pragmatics, the relationship of language to its real-life context. Within the field of cognitive semantics, however, these two concepts are considered inseparable from all other areas of linguistics. This approach to language attempts to demonstrate the ways that the mind uses language to organize experience, and vice-versa.
Syntax, for instance, is not separate from semantics because the grammatical components of a sentence have validity only as the mind is able to understand their meaning. To use a simple example, the statement "That is a porcupine" could be analyzed and broken down into its grammatical parts, but would still have no meaning outside of its context. That is, it would be a true statement if the speaker is, in fact, pointing to a porcupine, but a false statement if the speaker is pointing to a duck. It would have no meaning at all if the person hearing the statement could not see what the speaker was pointing to. Its meaning would be further obscured if the speaker was using "porcupine" in some metaphorical sense unknown to the hearer, or if the hearer had an incorrect notion of a porcupine.
Another way of saying this is that cognitive semantics is concerned primarily with the conceptual content of language. The mind, according to this theory, does not and cannot understand words or sentences in a vacuum, but by necessity understands them in relation to other experiences. Some approaches to linguistics assert that the brain has specialized functions for dealing with linguistic input, but cognitive linguists see this distinction as artificial. Neurolinguistic research on the subject is inconclusive.