MODAL VERBS: VOULOIR, DEVOIR, POUVOIR
Vouloir, devoir and pouvoir are called modal verbs. When used with infinitives, they act as auxiliary verbs or semi-auxiliaries.
Vouloir (to wish, want, will)
Vouloir expresses a strong will or desire; in the present tense it has the same feeling as a command. It is an irregular verb in the present tense. Note how the stems (in this case the vowels) change only in the nous and vous forms.