助動詞. Inflecting function words or endings such as 〜ます and 〜ない. Many inflect like verbs (such as 〜(ら)れる), but many others do not (such as 〜たい), so here we will call these simply "auxiliaries" and not "auxiliary verbs". These should be distinguished from 補助動詞（ほじょどうし）, which are tagged "subsidiary verbs" on this site to avoid confusion.
Called 助動詞【じょどうし】 in Japanese grammar, these are inflecting function words or endings such as 〜ます and 〜ない. Many inflect like verbs (such as 〜(ら)れる), but many others do not (such as 〜たい), so here we will call these simply "auxiliaries" and not "auxiliary verbs". These should be distinguished from 補助動詞（ほじょどうし）, which are tagged "subsidiary verbs" on this site to avoid confusion.
