Spanish irregular verbs

Spanish verbs are a complex area of Spanish grammar, with many combinations of tenses, aspects and moods (up to fifty conjugated forms per verb). While conjugation rules are relatively straightforward, a large number of verbs are irregular. Among these, some fall into more-or-less defined deviant patterns, while others are uniquely irregular. This article tries to summarize the common irregular patterns.

As in all Romance languages, many irregularities in Spanish verbs can be retraced to Latin grammar.

Vowel-alternating verbs

Vowel-alternating verbs, also known as stem-changing verbs, have two stems; one is the common infinitive stem (the one that serves to conjugate regular verbs) and the other derives from it by a vowel change. The change turns "e" into "ie" and "o" into "ue" when the syllable in question is stressed, which in effect happens only in the singular persons and third-person plural of the present indicative, present subjunctive, and present imperative. (Note that the dictionary form always has the vowel, not the diphthong, since in the infinitive form the stress is on the last syllable, i.e. on the thematic vowel.)

For example (only some persons and tenses, for contrasting purposes):
*"acertar" → "yo acierto, él acierta, nosotros acertamos, ellos aciertan; que yo acierte; yo acerté, él acertó..."
*"soldar" → "yo sueldo, él suelda, nosotros soldamos, ellos sueldan; que yo suelde; yo soldé, él soldó..."
*"perder" → "yo pierdo, él pierde, nosotros perdemos, ellos pierden; que yo pierda; yo perdí, él perdió..."
*"mentir" → "yo miento, él miente, nosotros mentimos, ellos mienten; que yo mienta; yo mentí, él mintió..."
*"apostar" → "yo apuesto, él apuesta, nosotros apostamos, ellos apuestan; que yo apueste; yo aposté, él apostó..."
*"moler" → "yo muelo, él muele, nosotros molemos, ellos muelen; que yo muela; yo molí, él molió..."

To complicate matters further, vowel-alternating verbs in the third conjugation ("-ir") furthermore change "e" to "i" and "o" to "u" in certain unstressed cases — the third person singular and plural of the preterite (and imperative, when the subjunctive is used as the imperative) and the second and third persons plural of the present subjunctive:

*"mentir" → "que yo mienta, que él mienta, que nosotros mintamos; yo mentí, él mintió, nosotros mentimos..."
*"concebir" → "yo concibo, él concibe, nosotros concebimos; yo concebí, él concibió..."

In some dialects, the second-person singular present tense is different, and gets stressed on the last syllable instead of the root, so the alternation does not take place: "tú pides" becomes "vos pedís", "tú mueres" becomes "vos morís". "See" Voseo for details.

Many verbs with "e" or "o" in the root do not alternate (e.g. "meter", "comer", etc.), and they are often a source of mistakes for children learning to speak, and also for some adults.
*"rebosar" → *"yo rebueso", *"él rebuesa..." instead of "yo reboso, él rebosa..."

G-verbs

The so-called "G"-verbs (sometimes "yo-go" verbs) add a medial "-g-" in the first person singular, present tense ("-ig-" when the root ends in a vowel). Many of these verbs are also irregular in other ways. For example:

:"poner: yo pongo, tú pones...":"tener: yo tengo, tú tienes...":"caer: yo caigo, tú caes...":"traer: yo traigo, tú traes...":"oír: yo oigo, tú oyes..."

Anomalous stems

Some verbs (including most "G"-verbs) have a completely different stem in the preterite. This stem is anomalous also because it is stressed in some persons (while in all other cases the preterite gets the stress over the suffix). These stems are very old and are often found in Latin as well.

:"poner" → "pus-": "yo puse, tú pusiste, él puso, nosotros pusimos...":"estar" → "estuv-": "yo estuve, tú estuviste, él estuvo, nosotros estuvimos...":"hacer" → "hic-, hiz-": "yo hice, tú hiciste, él hizo, nosotros hicimos...":"andar" → "anduv-": "yo anduve, tú anduviste, él anduvo, nosotros anduvimos...":"conducir" → "conduj-": "yo conduje, tu condujiste, él condujo, nosotros condujimos...":"decir" → "dij-": "yo dije, tú dijiste, él dijo, nosotros dijimos...":"tener" → "tuv-": "yo tuve, tú tuviste, él tuvo, nosotros tuvimos..."

Some verbs also change their stem in the future and conditional tenses::"tener" → "tendr-": "yo tendré, tú tendrás, él tendrá...":"hacer" → "har-": "yo haré, tú harás, él hará...":"decir" → "dir-": "yo diré, tú dirás, él dirá...":"haber" → "habr-": "yo habré, tú habrás, él habrá..."

Yet some other verbs take several different (but phonetically related) stems, in the most irregular fashion:

:"caber: yo quepo, tú cabes, él cabe...; yo cupe, tú cupiste, él cupo...":"saber: yo sé, tú sabes...; yo supe, tú supiste...; yo sabía, tú sabías...; yo sepa, tú sepas":"haber: yo he, tú has, él ha, nosotros hemos, vosotros habéis, ellos han"

Others

The verbs 'ser' (to be) and 'ir' (to go) both exhibit irregularities in the present, imperfect and preterite tenses.

;Present indicative tense

References

External links

* [http://www.webworkbooks.com/spanish/verbs/ WebWorkbooks: 10,000 verbs conjugated with voice files.]