'assibilation' originates from Latin, specifically the verb 'assibilare', where the prefix 'as-' (an assimilated form of 'ad-') meant 'to/toward' and 'sibilare' meant 'to hiss'.

'assibilare' (Latin) was used in Late/Medieval Latin formations and the English noun developed by combining the root with the suffix '-ation' (from Latin '-ationem' via Old French/Medieval Latin), eventually producing the modern English 'assibilation'.

Initially related to the action 'to hiss' or 'to make a hissing sound' in Latin, it developed into a technical linguistic term denoting the process by which sounds become sibilant.