köken: Inherited from Old Spanish alguien and the variations algui (c. 1260) and alguién (c. 16th c., but probably earlier). First attested in the form alguien in a 1247 document from San Esteban de Nogales. Two main etymologies have been suggested: * As a variant of alguno under the influence of, or conflated with, quien; probably originally being pronounced alguién (cf. Portuguese alguém, Galician…
köken: From late Old Swedish naghan, from earlier nokon, accusative of Old Swedish nokor, from Old Norse nǫkkurr, from Proto-Norse *ne-wait-ek-hwarjaʀ (literally, "not-know-I-who"). Cognate with Norwegian Nynorsk nokon, Danish nogen, Faroese nakar, Icelandic nokkur, Norwegian Bokmål noen.
köken: jo- (relative pronoun) + ku- (“who”). Originally an old compound of two pronominal stems, but is practically never considered a compound by speakers.
köken: Equivalent to iga (“every”) + üks (“one”). Possibly a calque from a Germanic language, compare English everyone, Dutch elkeen.
Igaüks ostis pudeli viina.
Igaühel on omaette tuba.
Igaühega luurele ei lähe.
Etimoloji
Inherited from Old Galician-Portuguese qual quer, from qual + quer. By surface analysis, qual (“which one”) + quer (“wants”). Compare Galician calquera, Spanish cualquiera, and Italian (literary) qualsivoglia.