language change
modification or development of a language
grammaticalization
process of language change by which words representing objects and actions become grammatical markers
suppletion
linguistic process in which inflections of etymologically unrelated stems come to be treated as the inflected forms of the same lexeme
phonological change
phenomenon in phonology
layering
principle by which grammaticalisation can be detected
agglutination
process in linguistic morphology derivation in which complex words are formed by stringing together morphemes without changing them in spelling or phonetics
sound change
process of language change affecting pronunciation or sound system structure
differentiation
process by which two closely related linguistic varieties diverge from one another during their evolution