standardisation

diachronic change

synchronic change

lexicon

political correctness

overt prestige

covert prestige

borrowing

eponym

proprietary names

acronym

initialism

clipping

affixation

prefixes

suffixes

conversion

compound

blend

obsolete

drift

amelioration

pejoration

weakening

narrowing (specialisation)

broadening (generalisation)

euphemism

idiom

archaism

influential power

instrumental power

omission

assimilation

informalisation

received pronunciation

divergence