Otros 'yo' irregulares: sé, doy, veo, quepo

Once you've covered the -go yo-irregulars (tengo, vengo, pongo, salgo, digo, oigo) and the -zco yo-irregulars (conozco, traduzco, conduzco), there are four high-frequency verbs whose yo form follows neither pattern. Each behaves like its own family of one. This page walks through all four — saber → sé, dar → doy, ver → veo, caber → quepo — with the full peninsular paradigm (including vosotros) and the spelling traps each one sets for learners.

Why these four are grouped together

The Spanish present tense has only a handful of verbs whose yo form is genuinely unpredictable from the infinitive. The two big productive groups (-go and -zco) account for most of them. What's left is this small, miscellaneous bag of historical leftovers — each verb preserves a quirk from Latin or Old Spanish that the rest of the language smoothed out.

You don't try to explain them with a rule. You learn the yo form, learn the rest of the paradigm (which is almost always regular from tú onward), and move on.

Saber — to know (facts, how to)

The verb saber means "to know" in the sense of knowing a fact, a piece of information, or knowing how to do something. (For knowing a person or a place, see conocer.) The yo form is sé, a single syllable carrying a written accent.

The accent on sé is doing real work

By Spain's accentuation rules, a single-syllable word does not normally take a written accent (fue, vio, dio, fui are all unaccented). So why does sé carry one?

Because of a rule called the tilde diacrítica ("distinguishing accent"). When two monosyllables would otherwise be spelled identically but mean different things, Spanish marks one of them with an accent to keep them apart in writing.

• se (with no accent) — the pronoun: reflexive (se lava), passive (se vende), or indirect object replacing le/les (se lo doy).
• sé (with accent) — the verb form: "I know" from saber, and also the tú imperative of ser ("be!").

In speech both are pronounced exactly the same. In writing, the accent is mandatory — a sentence like Yo se que tienes razón is a spelling error, not a stylistic choice.

Saber + infinitive = "to know how to"

A peninsular pattern worth flagging: saber + infinitive expresses "to know how to do something." English usually inserts "how"; Spanish doesn't.

Dar — to give

The verb dar ("to give") has a unique yo form: doy. The added -y is the same archaic ending that appears in soy (ser), estoy (estar), and voy (ir) — four old verbs that kept a Latin ending the rest of the language dropped.

The spelling trap in vosotros: dais has no accent

A learner who has internalized "vosotros forms always end in -áis with a written accent" (habláis, coméis, vivís) will instinctively want to write dáis. This is wrong.

The form dais is a single syllable: the a and i form a diphthong that the stress falls on, but it's still one syllable. Single-syllable words in Spanish do not take a written accent unless the tilde diacrítica requires it (as with sé above) — and dais has no homograph to disambiguate. So it stays unaccented: dais.

The same logic applies to dio and dieron in the preterite, and to fue, fui, vio — all single-syllable forms, all unaccented in modern peninsular orthography.

Ver — to see

The verb ver ("to see") is the exception that proves the rule about regular endings: its irregularity actually shows up across the whole paradigm, not just in the yo form. Ver keeps an extra -e- in every conjugation that other -er verbs lose.

Think of the stem as ve- rather than v-. Then the endings are completely regular -er endings tacked on.

Why veis has no accent

This is the same trap as dais. The vosotros ending of most -er verbs is -éis with a written accent (coméis, sabéis, tenéis). But veis is a single syllable — the e and i glide together into one diphthong, with no second syllable for the stress to be ambiguous about. Single syllables don't take accents (barring the tilde diacrítica). So: veis, plain, no accent.

A useful comparison:

• sabéis — two syllables (sa-béis), accent on the second.
• veis — one syllable, no accent needed.

This is one of the trickiest spelling details in the whole peninsular paradigm. Even Spaniards sometimes write véis by analogy, but the RAE-correct form is veis.

Caber — to fit

The verb caber ("to fit, to have room for") is the wildest of the four. Its yo form is quepo — the b of the infinitive vanishes, replaced by a p; the c of caber becomes qu before o to preserve the /k/ sound. This is a direct inheritance from Latin capere ("to take, to grasp"), where the same alternation existed.

The yo form is by far the most surprising — every other form looks like a perfectly regular -er verb. Most native speakers will tell you they go their whole life only ever needing cabe and caben ("it fits" / "they fit"). The yo form quepo is real and grammatical, but in everyday speech you'll mostly hear it about people fitting in spaces — and even then, native speakers often hedge with no quepo in self-deprecating contexts.

Caber has a useful idiomatic life

Caber is also used metaphorically to mean "to be possible" or "to be admissible" — common in formal and legal Spanish.

This (formal) register usage is worth recognizing in news and writing.

How English speakers compare these verbs

English collapses a lot of distinctions that Spanish keeps separate. A few notes:

• Saber vs. conocer: English uses "to know" for both knowing facts and knowing people. Spanish requires you to choose. Sé que vive en Madrid (I know that he lives in Madrid — fact) versus Conozco a Marta (I know Marta — acquaintance).
• Ver vs. mirar: Ver is passive perception ("to see"), mirar is active gaze ("to look at"). English often uses "see/watch/look" interchangeably; Spanish doesn't.
• Dar: covers a lot of metaphorical territory English splits across many verbs — dar un paseo (take a walk), dar miedo (to frighten), dar igual (to not matter), dar las gracias (to thank).
• Caber: English has no single verb that means quite this. "Fit" is closest, but English "fit" also covers quedar ("the shirt fits you") and encajar ("the pieces fit together") — three different Spanish verbs.

These irregularities propagate to the subjunctive

The yo forms above are the stem for the present subjunctive of these verbs. Once you know sé, doy, veo, quepo, the subjunctive falls out — sort of. The endings shift to -a class, but the irregular stem carries through (or, in the case of dar, the -y drops):

Note that dé in the subjunctive also carries an accent — this time to distinguish it from the preposition de ("of, from"). It's another tilde diacrítica. See diacritical accents for the full inventory.

Common mistakes

This is the cardinal error. English speakers regularize the verb by analogy with hablar → hablo. It feels logical, but it's not Spanish.

The pronunciation is identical, but in writing the accent is non-negotiable.

These two — dais and veis — are by far the most common spelling mistakes among learners (and among many native speakers texting fast). The rule is unintuitive: a written accent on a vosotros -éis ending feels automatic. But these two verbs land on single-syllable forms.

Key takeaways

• Four verbs with one-off yo forms: sé (saber), doy (dar), veo (ver), quepo (caber).
• Sé takes a written accent because of the tilde diacrítica — to distinguish it from the pronoun se.
• Dais and veis are single syllables and therefore do not take a written accent, breaking the -éis pattern.
• Ver keeps an extra -e- throughout the paradigm — its stem is effectively ve-, not v-.
• Caber gives quepo (irregular yo), but the rest of the paradigm is regular.
• These irregular yo forms become the stems of the corresponding present subjunctives: sepa, dé, vea, quepa. Dé also carries an accent — for the same diacritical reason as sé.