swallowyoudaoicibaDictYouDict[swallow 词源字典]
swallow: English has two distinct words swallow. The verb, ‘ingest’ [OE], comes from a prehistoric Germanic *swelgan, which also produced German schwelgen, Dutch swelgen, Swedish svälja, and Danish svælge. It was formed from a base which also gave Old Norse svelgr ‘whirlpool, devourer’. Swallow the bird [OE] comes from a prehistoric Germanic *swalwōn, which also produced German schwalbe, Dutch zwaluw, Swedish svala, and Danish svale and is probably related to Russian solovej ‘nightingale’.
[swallow etymology, swallow origin, 英语词源]
swallow (v.)youdaoicibaDictYouDict
"ingest through the throat" (transitive), Old English swelgan "swallow, imbibe, absorb" (class III strong verb; past tense swealg, past participle swolgen), from Proto-Germanic *swelgan/*swelhan (cognates: Old Saxon farswelgan, Old Norse svelgja "to swallow," Middle Dutch swelghen, Dutch zwelgen "to gulp, swallow," Old High German swelahan "to swallow," German schwelgen "to revel"), probably from PIE root *swel- (1) "to eat, drink" (cognates: Iranian *khvara- "eating").

Intransitive sense "perform the act of swallowing" is from c. 1700. Sense of "consume, destroy" is attested from mid-14c. Meaning "to accept without question" is from 1590s. Related: Swallowed; swallowing.
swallow (n.1)youdaoicibaDictYouDict
type of migratory bird (family Hirundinidae), Old English swealwe "swallow," from Proto-Germanic *swalwon (cognates: Old Saxon, Old Norse, Old Frisian, Swedish svala, Danish svale, Middle Dutch zwalewe, Dutch zwaluw, Old High German swalawa, German Schwalbe), from PIE *swol-wi- (cognates: Russian solowej, Slovak slavik, Polish słowik "nightingale"). The etymological sense is disputed. Popularly regarded as harbingers of summer; swallows building nests on or near a house is considered good luck.
swallow (n.2)youdaoicibaDictYouDict
"an act of swallowing," 1822, from swallow (v.). In late Old English and Middle English it meant "gulf, abyss, hole in the earth, whirlpool," also, in Middle English, "throat, gullet." Compare Old Norse svelgr "whirlpool," literally "devourer, swallower." Meaning "as much as one can swallow at once, mouthful" is from 1861.