> Etymology: Old English had two verbs: (1) the primary strong verb dúfan , past tense déaf , plural dufon , past participle dofen , intransitive to duck, dive, sink; (2) the derivative causal weak verb dýfan , dýfde , gedýfd to dip, submerge. Already in 12th cent. these had begun to be confounded, the primary dūven (past tense deæf , dêf , past participle doven ) being used also transitive, and the causative dȳven intransitive, so that the two became synonyms, and before 1300 the strong verb became obsolete, dȳven (south-western düven , south-eastern dēven , midland and north dīven ) remai…