Stem Changing Verbs

There are four types of stem-changing verbs in Spanish: e to ie, e to i, o to ue, and u to ue. These stem changes only occur in the singular and third-person plural forms in the present tense. Some verbs with spelling changes are oler, which changes o to hue; reir and sonreir, which add an accent to the i; and seguir, which changes gu to g before o and a.