Present tense: -UIR verbs that add Y
Some Spanish verbs ending in -uir add the letter y in several present-tense forms. The pattern is predictable: yo, tú, él, ella, usted, ellos, ellas and ustedes add y; nosotros and vosotros do not.
The u never changes into y and never disappears. Remove -ir to find the stem, keep its u, add y where the pattern requires it, and then add the regular -IR person ending.
1. Add Y without removing the U
For construir, remove -ir to get constru-. In the forms that add y, combine constru- + y + the regular ending: construyo, construyes, construye and construyen. With nosotros and vosotros, use construimos and construís without y.
2. The regular -IR endings still matter
The added y belongs to the stem pattern; the ending still identifies the subject. Nosotros uses -imos, vosotros uses -ís, and the written accent in -ís is required.
3. Useful verbs and structures
Learn each verb with the words and prepositions it normally uses. The conjugation can be correct while the surrounding structure is still incomplete.
4. Compare a regular -IR verb
The y-pattern belongs only to selected verbs. A regular -IR verb such as vivir keeps its stem in every present form.
5. Do not apply this pattern to -GUIR verbs
Common verbs ending in -guir follow other spelling or stem patterns. Seguir, conseguir and distinguir do not use the basic construyo pattern.
6. Oír and leer are different
Oír contains y in some forms, but it combines several irregularities and belongs with the yo-go verbs: oigo, oyes, oye, oímos, oís, oyen. Leer is not an -UIR verb and remains leo, lees, lee, leemos, leéis, leen.
7. Subjects, negatives and questions
A name or noun group determines the form just like a pronoun. One person uses a singular form, two or more people use a plural form, and a group including the speaker uses nosotros. Spanish often omits the pronoun when the ending makes the subject clear.
Put no directly before the conjugated verb. Questions use the conjugated form directly, without an English-style do or does.
8. A reliable method
Identify the infinitive and confirm that it belongs to this -UIR group. Remove -ir, identify the subject, and decide whether it is nosotros or vosotros. Add y in the other forms, then attach the regular -IR ending and read the full sentence again.
8. Common mistakes
Add y between the stem and the ending.
Keep the u; it does not change into y.
Nosotros does not add y.
Vosotras does not add y, and -ís needs an accent.
Use written y, not i.
Contribuir normally uses a with a project or cause.
Use sustituir algo por otra cosa.
Do not apply the pattern to every -IR verb.
Seguir is a separate -GUIR pattern.
9. A reliable method
- Identify the infinitive and confirm that it belongs to the -UIR + y group.
- Remove -ir and keep the complete stem, including u.
- Identify the subject.
- With nosotros or vosotros, do not add y; with the other present forms, add y.
- Add the regular -IR person ending and check required accents and prepositions.