-t

From Middle English -te (past tense ending), -t (past participle ending), from Old English -te, -de (first and third person past tense ending), -t, -ed, -od (past participle ending), from Proto-Germanic *-id- (past tense stem ending of class 1 weak verbs) and *-idaz (past participle ending of class 1 weak verbs).

In some verbs, like lose/lost, the ‐t‐/‐t arose during the Middle English period from the devoicing of the earlier ‐d‐/‐d. This devoicing typically occurred after the suffix was syncopated from ‐ede and ‐ed, forcing the voiced alveolar stop directly against the stem’s final consonant. See -ed (etymologies 1 and 2). Furthermore, in forms such as spelt and burnt, the participial -t is a later development during the Early Modern English period.

From Middle English -t (e.g. aȝenst vs. aȝens (“against”)), likely resulting from -s + the, or various other words beginning with th-, t-.

From Middle English -t, from Old English -t, variant of -þ (“-th”) following spirant/fricative sounds, from Proto-Germanic *-þiz. More at -th.

Suffix from Middle English -ten, from Old English -ettan, from Proto-West Germanic *-attjan, from Proto-Germanic *-atjaną.