The emergence of new structures in the language through pressures from social group differentiation and stylistic variation over historical time. Diachronic linguistics is the study of language change over such time. ‘Diachronic’ is from the Greek dia meaning ”through’ and chronos meaning ‘time’, and is opposed with ‘synchronic’ standing for ‘at one point in time’.
See Developmental emergence, Emergence, Epigenetic emergence, Evolutionary emergence, Language development, Linguistics