Linguistics is the study of human language, and has several major divisions: formal linguistics, sociolinguistics, psycholinguistics, and applied linguistics. Formal linguistics is the study of grammar, or the development of theories about how language works and is organized. Within formal linguistics there are three major schools of thought: traditional, structural, and generative/transformational grammar. The principal areas of study within the field are phonetics, phonology, morphology, syntax, and semantics. Sociolinguistics is the study of language as a social and cultural phenomenon, and includes the study of language variation, language and social interaction, language attitudes, and language planning. Psycholinguistics is the study of the relationship between linguistic and psychological behavior, including first and second language acquisition, the relationship of language and cognition, and the processes by which humans store and retrieve linguistic information. Applied linguistics is concerned with the use of linguistic research findings for the solution of practical problems and for innovation in everyday language matters such as language teaching, literacy education, development of grammars and alphabets for unwritten languages, lexicography, legal matters involving language, and speech synthesis and recognition. (MSE)