Stem-changing Spanish c>z verbs in the present tense
Spanish verbs that end in consonant + -cer/-cir change the -c- for a -z- in the yo form. For example vencer (to win):| yo | venzo | 
| tú | vences | 
| él / ella / Ud. | vence | 
| nosotros / nosotras | vencemos | 
| vosotros / vosotras | vencéis | 
| ellos / ellas / Uds. | vencen |