phonetics - is a related branch of linguistics concerned with the actual properties of speech sounds (phones), non-speech sounds, and how they are produced and perceived.
evolutionary linguistics which considers the origins of language
historical linguistics which explores language change
sociolinguistics which looks at the relation between linguistic variation and social structures
psycholinguistics which explores the representation and functioning of language in the mind
neurolinguistics which looks at the representation of language in the brain
language acquisition which considers how children acquire their first language and how children and adults acquire and learn their second and subsequent languages
discourse analysis is concerned with the structure of texts and conversations
pragmatics with how meaning is transmitted based on a combination of linguistic competence, non-linguistic knowledge, and the context of the speech act
the study of language-related issues applied in everyday life, notably language policies, planning, and education. (Constructed language fits under Applied linguistics.)
the study of natural as well as human-taught communication systems in animals, compared to human language.
the application of linguistic theory to the field of Speech-Language Pathology.
the study of computational implementations of linguistic structures.
the study of the development of linguistic ability in individuals, particularly the acquisition of language in childhood.
the study of the geographical distribution of languages and linguistic features.
the study of the common properties of diverse unrelated languages, properties that may, given sufficient attestation, be assumed to be innate to human language capacity.
Semantics (language meaning) - in linguistics, semantics is the subfield that is devoted to the study of meaning, as inherent at the levels of words, phrases, sentences, and larger units of discourse.
Grammar (language structure) - in linguistics, grammar refers to the logical and structural rules that govern the composition of sentences, phrases, and words in any given natural language.
Semiotics - a related field concerned with the general study of signs and symbols both in language and outside of it
Literary theorists study the use of language in artistic literature.
Ferdinand de Saussure (26 November 1857 – 22 February 1913) was a Swiss linguist whose ideas laid a foundation for many significant developments in linguistics in the 20th century. Saussure is widely considered to be one of the fathers of 20th-century linguistics, and his ideas have had a monumental impact on literary and cultural theory and interpretation.
Jacob Ludwig Carl Grimm (Hanau, January 4, 1785 – September 20, 1863 in Berlin), German philologist, jurist and mythologist, was born at Hanau, in Hesse-Kassel (or Hesse-Cassel). He is best known as the discoverer of Grimm's Law, the author of the monumental German Dictionary, his Deutsche Mythologie and more popularly, as one of the Brothers Grimm, as the editor of Grimm's Fairy Tales.