8.2.14
Irregular IR Verbs (2/6)
Radical Changing Stems (O → U)
Radical Changing Stems (O → U)
In the preterite tense, some verbs change their stems in the 'él/ella' and 'ellos/ellas' forms, with the 'o' changing to a 'u'. The two verbs that follow this pattern are 'morir' and 'dormir'.


Morir - to die
Morir - to die
- Morí - I died.
- Moriste - you died.
- Murió - he/she died.
- Morimos - we died.
- Moristeis - you died.
- Murieron - they died.


Dormir - to sleep
Dormir - to sleep
- Dormí - I slept.
- Dormiste - you slept.
- Durmió - he/she slept.
- Dormimos - we slept.
- Dormisteis - you slept.
- Durmieron - they slept.
Irregular IR verbs
Irregular IR verbs
In the preterite tense, there are lots of verbs that change their stem or follow a different pattern to regular verbs. Here are some examples:


Changing stem (e → i)
Changing stem (e → i)
- Some IR verbs in the preterite tense change their stem.
- In the 'él/ella' and the 'ellos/ellas' forms, the 'e' changes to an 'i'.
- For example, elegir - to choose.
- Elegí - I chose.
- Elegiste - you chose.
- Eligió - he/she chose.
- Elegimos - we chose.
- Elegisteis - you chose.
- Eligieron - they chose.


Changing stem (o → u)
Changing stem (o → u)
- In the preterite tense, some verbs change their stems in the 'él/ella' and 'ellos/ellas' forms, with the 'o' changing to a 'u'.
- The two verbs that follow this pattern are 'morir' and 'dormir'.
- E.g. dormir - to sleep:
- Dormí - I slept.
- Dormiste - you slept.
- Durmió - he/she slept.
- Dormimos - we slept.
- Dormisteis - you slept.
- Durmieron - they slept.


Changing stem (i → y)
Changing stem (i → y)
- Most IR verbs that end in 'uir' change their stem in the 'él/ella' and 'ellos/ellas' forms of the preterite tense.
- These verbs drop the 'i' from the stem and instead have a 'y'.
- E.g. contribuir - to contribute:
- Contribuí - I contributed.
- Contribuiste - you contributed.
- Contribuyó - he/she contributed.
- Contribuimos - we contributed.
- Contribuisteis - you contributed.
- Contribuyeron - they contributed.


Verbs ending in 'ducir'
Verbs ending in 'ducir'
- Verbs that end in 'ducir' change the 'c' to a 'j' in a preterite tense.
- E.g. introducir - to introduce
- Introduje - I introduced.
- Introdujiste - you introduced.
- Introdujo - he/she introduced.
- Introdujimos - we introduced.
- Introdujisteis - you introduced.
- Introdujeron - they introduced.


Decir - to say
Decir - to say
- 'Decir' is a strong preterite that follows two patterns: its root vowel changes from an 'e' to an 'i' and a 'j' is added to its stem:
- Dije - I said.
- Dijiste - you said.
- Dijo - he/she said.
- Dijimos - we said.
- Dijisteis - you said.
- Dijeron - they said.


Ir - to go & ser - to be
Ir - to go & ser - to be
'Ir' is a strong preterite that follows the same irregular pattern as 'ser':
- Fui - I went/was.
- Fuiste - you went/were.
- Fue - he/she/it went/was.
- Fuimos - we went/were.
- Fuisteis - you went/were.
- Fueron - they went/were.
1The Basics
1.1Pronouns
1.2Verbs
1.3Nouns
1.4Adjectives
1.5Abbreviations
2Home & Abroad
2.2Holiday
2.4Everyday Life, Traditions & Communities
3Education & Employment
3.2School Trips
3.4Future Plans
4Personal Life & Relationships
4.1House & Home
4.2Daily Routines & Helping at Home
4.3Family & Friends
5The World Around Us
5.1Environmental Issues
5.2Weather
5.3Travel & Transport
5.5Information & Communication
6Social Activities, Fitness & Health
6.1Special Occasions
6.2Hobbies & Interests
6.3Shopping & Money Matters
6.4Injuries, Illness & Health
7Listening
7.1Town & Region
7.2Holiday
7.3Customs
7.4Education
7.5Personal Life & Relationships
7.6The Media & Technology
7.7Social Activities
7.8The Environment
7.9Fitness & Health
8Common Tenses
8.1Present Tense
8.1.1Regular AR Verbs
8.1.2Negative Verbs
8.1.3Irregular AR Verbs
8.1.4Irregular AR Verbs: Exceptions
8.1.5Regular ER Verbs
8.1.6Irregular ER Verbs
8.1.7Irregular ER Verbs 2
8.1.8Regular IR Verbs
8.1.9Irregular IR Verbs
8.1.10Irregular IR Verbs 2
8.1.11Irregular IR Verbs 3
8.1.12Irregular IR Verbs 4
8.1.13Verb Phrases
8.1.14The Use of 'Se'
8.2Preterite Tense
8.2.1Regular AR Verbs
8.2.2Irregular AR Verbs (1/4)
8.2.3Irregular AR Verbs (2/4)
8.2.4Irregular AR Verbs (3/4)
8.2.5Irregular AR Verbs (4/4)
8.2.6Regular ER Verbs
8.2.7Irregular ER Verbs (1/5)
8.2.8Irregular ER Verbs (2/5)
8.2.9Irregular ER Verbs (3/5)
8.2.10Irregular ER Verbs (4/5)
8.2.11Irregular ER Verbs (5/5)
8.2.12Regular IR Verbs
8.2.13Irregular IR Verbs (1/6)
8.2.14Irregular IR Verbs (2/6)
8.2.15Irregular IR Verbs (3/6)
8.2.16Irregular IR Verbs (4/6)
8.2.17Irregular IR Verbs (5/6)
8.2.18Irregular IR Verbs (6/6)
8.3Imperfect Tense
8.4Preterite vs Imperfect Tenses
8.5Future Tense
9Important Verbs
9.1To Be - 'Ser' & 'Estar'
9.2To Like - 'Gustar'
9.3To Have - 'Tener'
10Advanced Tenses
10.1The Simple Future
10.2Conditional Tense
10.3Continuous Tenses
10.4Perfect Tense
10.5Present Subjunctive
10.5.1Present Subjunctive: AR Verbs
10.5.2Present Subjunctive: ER Verbs
10.5.3Present Subjunctive: IR Verbs
10.5.4Irregular AR Verbs (1/3)
10.5.5Irregular AR Verbs (2/3)
10.5.6Irregular AR Verbs (3/3)
10.5.7Irregular ER Verbs (1/2)
10.5.8Irregular ER Verbs (2/2)
10.5.9Irregular IR Verbs (1/3)
10.5.10Irregular IR Verbs (2/3)
10.5.11Irregular IR Verbs (3/3)
10.5.12The Verb 'Ir'
10.5.13Subjunctive Uses
10.6Imperfect Subjunctive
11Extra Grammar
11.2Negatives
11.3Nouns
11.4Asking Questions
11.5Adjectives
11.6Adverbs
11.7Conjunctions
11.8Pronouns
11.9By, With, From, Of
11.10Verbs
11.11Comparisons
Jump to other topics
1The Basics
1.1Pronouns
1.2Verbs
1.3Nouns
1.4Adjectives
1.5Abbreviations
2Home & Abroad
2.2Holiday
2.4Everyday Life, Traditions & Communities
3Education & Employment
3.2School Trips
3.4Future Plans
4Personal Life & Relationships
4.1House & Home
4.2Daily Routines & Helping at Home
4.3Family & Friends
5The World Around Us
5.1Environmental Issues
5.2Weather
5.3Travel & Transport
5.5Information & Communication
6Social Activities, Fitness & Health
6.1Special Occasions
6.2Hobbies & Interests
6.3Shopping & Money Matters
6.4Injuries, Illness & Health
7Listening
7.1Town & Region
7.2Holiday
7.3Customs
7.4Education
7.5Personal Life & Relationships
7.6The Media & Technology
7.7Social Activities
7.8The Environment
7.9Fitness & Health
8Common Tenses
8.1Present Tense
8.1.1Regular AR Verbs
8.1.2Negative Verbs
8.1.3Irregular AR Verbs
8.1.4Irregular AR Verbs: Exceptions
8.1.5Regular ER Verbs
8.1.6Irregular ER Verbs
8.1.7Irregular ER Verbs 2
8.1.8Regular IR Verbs
8.1.9Irregular IR Verbs
8.1.10Irregular IR Verbs 2
8.1.11Irregular IR Verbs 3
8.1.12Irregular IR Verbs 4
8.1.13Verb Phrases
8.1.14The Use of 'Se'
8.2Preterite Tense
8.2.1Regular AR Verbs
8.2.2Irregular AR Verbs (1/4)
8.2.3Irregular AR Verbs (2/4)
8.2.4Irregular AR Verbs (3/4)
8.2.5Irregular AR Verbs (4/4)
8.2.6Regular ER Verbs
8.2.7Irregular ER Verbs (1/5)
8.2.8Irregular ER Verbs (2/5)
8.2.9Irregular ER Verbs (3/5)
8.2.10Irregular ER Verbs (4/5)
8.2.11Irregular ER Verbs (5/5)
8.2.12Regular IR Verbs
8.2.13Irregular IR Verbs (1/6)
8.2.14Irregular IR Verbs (2/6)
8.2.15Irregular IR Verbs (3/6)
8.2.16Irregular IR Verbs (4/6)
8.2.17Irregular IR Verbs (5/6)
8.2.18Irregular IR Verbs (6/6)
8.3Imperfect Tense
8.4Preterite vs Imperfect Tenses
8.5Future Tense
9Important Verbs
9.1To Be - 'Ser' & 'Estar'
9.2To Like - 'Gustar'
9.3To Have - 'Tener'
10Advanced Tenses
10.1The Simple Future
10.2Conditional Tense
10.3Continuous Tenses
10.4Perfect Tense
10.5Present Subjunctive
10.5.1Present Subjunctive: AR Verbs
10.5.2Present Subjunctive: ER Verbs
10.5.3Present Subjunctive: IR Verbs
10.5.4Irregular AR Verbs (1/3)
10.5.5Irregular AR Verbs (2/3)
10.5.6Irregular AR Verbs (3/3)
10.5.7Irregular ER Verbs (1/2)
10.5.8Irregular ER Verbs (2/2)
10.5.9Irregular IR Verbs (1/3)
10.5.10Irregular IR Verbs (2/3)
10.5.11Irregular IR Verbs (3/3)
10.5.12The Verb 'Ir'
10.5.13Subjunctive Uses
10.6Imperfect Subjunctive
11Extra Grammar
11.2Negatives
11.3Nouns
11.4Asking Questions
11.5Adjectives
11.6Adverbs
11.7Conjunctions
11.8Pronouns
11.9By, With, From, Of
11.10Verbs
11.11Comparisons
Unlock your full potential with Seneca Premium
Unlimited access to 10,000+ open-ended exam questions
Mini-mock exams based on your study history
Unlock 800+ premium courses & e-books