Verbs Ending in -air

Verbs whose infinitive ends in -air form a tight, high-frequency family in European Portuguese. There are only three base verbs — sair (to go out, to leave), cair (to fall), and trair (to betray) — but they come loaded with common compounds: atrair (to attract), distrair (to distract), retrair (to retract, withdraw), contrair (to contract), extrair (to extract), subtrair (to subtract). Every member of this class conjugates identically, so once you know sair, you know all nine verbs plus any others that end in -air.

What makes the class distinctive is a single recurring orthographic feature: whenever the stem-final -a- and the ending -i- are pronounced as two separate syllables (a hiatus), the i carries a written acute accent. This is the difference between sais (one syllable, diphthong) and saíste (two syllables, sa-ÍS-te). The accent is not decorative — it is the language telling you explicitly where to break the syllables.

The core pattern

The stem of sair, cair, trair is a bare s-, c-, tr- plus the vowel a. When you add the regular -ir endings, the resulting paradigm has three key features:

1. The 1sg present inserts a glide between the a of the stem and the o of the ending: saio, caio, traio. Without the glide, the form would be unpronounceable as sa-o.
2. Wherever the ending contains an i that is pronounced as its own syllable — that is, whenever -a- and -i- do not form a diphthong — the i takes an acute accent: saíste, caímos, traíram.
3. The diphthong forms (sais, sai, saem) do not carry any accent, because the -ai- and -ae- are pronounced as single-syllable glides.

Sair (to go out, to leave) — full paradigm

Present indicative

Preterite (perfective past)

Notice that every form in the preterite carries the accented í except the 3sg saiu, because saiu is pronounced as a single diphthong (sa-IU) rather than a hiatus. The accent rule is phonological: accent wherever the two vowels are pronounced separately, leave bare wherever they form a diphthong.

Note that saímos is the same form for present and preterite. European Portuguese disambiguates present from preterite in -ar verbs with the acute on passámos vs passamos, but -ir verbs like sair have identical spelling in both tenses. Context decides. The same holds for caímos and traímos.

Imperfect

Every imperfect form takes the accented í, because every ending creates a hiatus (the -ia- of saía is pronounced sa-I-a, three syllables, not sai-a).

Future and conditional

In the future and conditional, the infinitive sair is fully preserved as the stem, so no accent is needed on the -ai- — it is pronounced as a diphthong (sai-REI, sai-RIA). The only place an accent appears is in the 1pl conditional sairíamos, where the -í- ending creates a hiatus of its own.

Present subjunctive

The present subjunctive is built on the 1sg indicative stem (saio → sai-) plus the -a endings. No accent is needed — saia, saias, saiamos are all pronounced with the -ai- as a diphthong or glide.

Imperfect subjunctive and personal infinitive

The imperfect subjunctive and the personal infinitive both take accented forms where hiatus occurs: saísse, saísses, saísse, saíssemos, saíssem (imperfect subjunctive) and sair, saíres, sair, sairmos, saírem (personal infinitive).

Cair (to fall)

Cair follows the identical paradigm — just substitute c- for s- at the start of every form.

Cair has a rich set of idiomatic uses: cair bem / mal (to suit / not suit — of clothes or food), cair em si (to come to one's senses), cair no esquecimento (to fall into oblivion), cair na real (to face reality).

Trair (to betray)

Same paradigm, stem tr-.

Trair has a broader semantic range than English betray: it can mean "to give away, reveal (unintentionally)," as in the second example above.

The compounds of -trair

The compounds of trair — formed with Latin-origin prefixes — conjugate identically but carry quite different meanings:

Past participle and gerund

The past participle of -air verbs always takes the accented í (hiatus): saído, caído, traído, atraído, distraído, extraído. The gerund does not take the accent, because the -ai- is a diphthong: saindo, caindo, traindo, atraindo, distraindo, extraindo.

Notice how distraído (past participle, hiatus, accented) and distraindo (gerund, diphthong, no accent) differ by a single letter — the accent is doing real work.

The imperative

The imperative follows the general Portuguese pattern:

• Affirmative tu = 3sg present indicative = sai, cai, trai.
• Negative tu / affirmative and negative você/vocês = present subjunctive = (não) saias, (não) caias, (não) traias / saia, caia, traia / saiam, caiam, traiam.

Distinguishing hiatus from diphthong

If there is one idea to carry away from this class, it is the distinction between hiatus (two vowels in two syllables) and diphthong (two vowels in one syllable). Portuguese spelling marks hiatus with an accent on the í so that readers can tell the difference at a glance.

A single useful rule: if the stress falls on the i of the ending, write í. If the stress does not fall on the i — if the i is a semivowel — write i with no accent.

Spanish comparison

Spanish has cognate verbs: salir, caer, traer (though note traer is -er, not -ir). The Portuguese paradigm is different in several ways:

• Portuguese has -air where Spanish has -alir or -aer. The infinitive and stem shape are different.
• Spanish salir is heavily irregular (salgo, sales, sale, salimos, salís, salen) in the 1sg. Portuguese sair is much closer to regular.
• Spanish caer has caigo in 1sg and marked imperfect caía. Portuguese cair has caio and caía — the Portuguese 1sg is simpler.
• Spanish does not accent hiatus the way Portuguese does in these paradigms — Spanish writes caí, caíste with accents that mark stress, but the system is different.

The main takeaway: the Portuguese -air class is internally simpler than the Spanish cognates, but the hiatus accent is a distinctive feature that Spanish-speakers need to learn fresh.

English comparison

English has no verb-class distinctions remotely like this one. The closest analogy is the irregular past participle fallen (from fall) which shows a vowel change — but English has no systematic accent marking hiatus, because English does not generally have hiatus-vs-diphthong distinctions in written form. An English speaker simply has to learn to read the accent as a syllable-break instruction: saíste is three syllables, sais is one.

Common Mistakes

Without the accent, a reader cannot tell whether saimos is a hiatus (two syllables) or an attempted diphthong. Portuguese orthography requires the accent to resolve the ambiguity.

The 1sg (caio) ends in -o; the 3sg preterite (caiu) ends in -u. A single letter separates them and they mean very different things.

The opposite error is overcorrection: learners who have internalized the accent rule sometimes add an accent where none is needed. Saias (subjunctive) has no accent because -ai- here is a diphthong; saías (imperfect indicative) has an accent because -í- there is stressed and stands alone.

Key takeaways

• The -air class has three base verbs — sair, cair, trair — plus six common compounds of -trair. All conjugate identically.
• The 1sg present inserts a glide: saio, caio, traio.
• Wherever the -a- of the stem and the -i- of the ending form a hiatus (two syllables), the i takes a written acute accent: saíste, caímos, traíram, saía, saído.
• Wherever they form a diphthong (one syllable), no accent: sais, sai, saem, saiu, saia, saindo.
• The accent rule is not decorative — it tells you how many syllables the word has.
• The past participle is accented (saído), the gerund is not (saindo).
• Affirmative tu imperative = 3sg present (sai, cai, trai); negative tu and você use the subjunctive (não saias, saia).