köken: From Middle French tousjours, from Old French toz jorz, tuzjurz (“without ceasing”, literally “all days”). By surface analysis, tous + jours (compare Dutch altijd (“always”), Danish altid (“always”)). Replaced Old French sempres (“always”), from Latin semper. Cognate with Catalan and Occitan totjorn.
aile: cause toujours, de toujours, depuis toujours, encore et toujours, toujours est-il que
Il est toujours en retard.
Parfois, peut-être même souvent, mais certainement pas toujours
köken: From Proto-Finnic *aina (compare Estonian aina), probably borrowed from Proto-Balto-Slavic [Term?] (compare Old Prussian ainat (“always, constantly”) and Lithuanian vienàt (“only”)).
Inherited from Old East Slavic вьсегда (vĭsegda), from Proto-Slavic *vьśegъda. The все part is related to весь meaning "all, every, the whole". The -гда ending is also found in когда, see the etymology there. This ending may have derived from the genitive of год (god, “period of time”). See also годъ, тогда.