What are the stem changers in Spanish

In Spanish, stem-changing verbs (also known as "boot verbs" or "shoe verbs") are verbs that change in the stem when conjugated in the present tense, and sometimes in other tenses and moods. The change occurs in the last vowel of the verb stem in all forms except nosotros and vosotros, which is why they are called "boot" or "shoe" verbs – if you were to circle the conjugations that change in a conjugation chart, it would look like a boot or a shoe.

The stem changes can be categorized into three main types:

1. **e -> ie**: The vowel "e" in the stem changes to "ie" for certain subjects. For example, the verb "pensar" (to think) is conjugated as "yo pienso" (I think), not "yo penso." 2. **o -> ue**: The vowel "o" in the stem changes to "ue." For instance, "dormir" (to sleep) becomes "yo duermo" (I sleep), not "yo dormo." 3. **e -> i**: The vowel "e" changes to an "i." This happens in verbs like "pedir" (to ask/order), which is conjugated as "yo pido" (I ask/order).

There is a fourth, less common type of stem change that occurs with some verbs:

4. **u -> ue**: This occurs in only a few verbs, like "jugar" (to play [games or sports]), which becomes "yo juego."

When conjugating stem-changing verbs, remember that the stem change applies to every form in the present tense except for nosotros and vosotros forms. Here is an example with the verb "pensar":

- Yo pienso (I think) - Tú piensas (You think) - Él/Ella/Usted piensa (He/She thinks, You (formal) think) - Nosotros pensamos (We think) - Vosotros pensáis (You all think) [No stem change] - Ellos/Ellas/Ustedes piensan (They think, You all (formal) think)