⇒ Spanish irregular present tense verbs fall into various categories: verbs with irregular yo forms in the present indicative, stem-changing verbs, spelling-change verbs, and verbs that are irregular in all forms.

⇒ Some present tense yo conjugations undergo spelling changes or are irregular.

⇒ Verbs that end in -guir, -ger, or -gir undergo a spelling change in their present tense yo forms.

• For verbs that end in -guir, the yo form ends in go.
• For verbs that end in -ger or -gir, the g in the yo form changes to a j.

⇒ The following verbs have irregular yo forms. The other present tense forms of these verbs follow the patterns for regular -ar, -er, and -ir verbs.

⇒ Most verbs that end in -cer or -ucir have irregular present tense yo forms.

⇒ Verbs made of up the above forms plus a prefix are also irregular in the yo form. Check out these examples.

⇒ There are a number of verbs that have irregular forms other than the yo form.

⇒ These include stem-changing verbs, spelling-change verbs, and verbs that are considered truly irregular.

⇒ Four of the most frequently-used verbs in Spanish (ser, estar, ir, and haber) are irregular. The present indicative conjugations for each are given below.