Grammar Tips (#2): ão or am?

While the issues surrounding nasal vowels are more complicated than the scope of this post (and one I’ll try to work on another date), some people struggle with knowing whether to place -ão ou –am at the end of a word with the nasal diphthong ɐ̃w.

#1: -ão is used on nouns and all verbs in the indicative future for the 3rd person plural

If you have a noun ending in this nasal sound, it will always have -ão:

  • [o] cão (dog)
  • [o] colchão (mattress)
  • [a] estação (station)
  • [a] televisão (TV), from [a] visão (vision)

-ão is also used to form masculine augmentatives out of other nouns:

  • [o] canzarrão (big dog)
  • [o] cavalão (big horse)
  • [o] gatarrão (big cat)

All verbs in the 3rd person plural (“they”) indicative future have –ão (actually –rão) as their tense ending:

  • cantar (to sing): Elas/Eles cantarão
  • saber (to know): Elas/Eles saberão
  • viver (to live): Elas/Eles viverão
  • vir (to come): Elas/Eles virão

Some irregular verbs go against this rule in the indicative present, adding -ão to their 3rd person plural forms there as well:

  • ir (to go): Elas/Eles vão (They go), but also Elas/Eles irão (They will/shall go)
  • ser (to be): Elas/Eles são (They are), but also Elas/Eles serão (They will/shall be)
  • estar (to be): Elas/Eles estão (They are), but also Elas/Eles estarão (They will/shall be)

#2: -am is used in every other verb tense where it would apply.

  • The indicative present, imperfect, preterite, imperfect, pluperfect and conditional of regular verbs ending in -ar: cantar (to sing)
    • Elas/Eles cantam (indicative present)
    • Elas/Eles cantaram (preterite/pluperfect)*
    • Elas/Eles cantavam (indicative imperfect)
    • Elas/Eles cantariam (conditional)
  • The preterite, pluperfect, imperfect, conditional, present subjunctive and imperative of regular verbs ending in -er and -ir: comer (to eat) / fingir (to fake, to pretend)
    • Elas/Eles comeram / fingiram (preterite/pluperfect)*
    • Elas/Eles comiam / fingiam (indicative imperfect)
    • Elas/Eles comeriam / fingiriam (conditional)
    • Elas/Eles comam / finjam (present subjunctive)
    • [Elas/Eles] comam! / finjam! (imperative)
  • The preterite, pluperfect, imperfect and conditional of all irregular verbs (other tenses may carry it, but those vary from verb to verb: ser (to be) / ir (to go)
    • Elas/Eles foram (preterite/pluperfect)+
    • Elas/Eles eram / iam (indicative imperfect)
    • Elas/Eles seriam / iriam (conditional)

Note: all verbs share a form in the 3rd person plural on the preterite and pluperfect

The verbs ser (“to be”) and ir (“to go”) share all forms on the preterite and pluperfect

#3: The difference is one of stress: -ão is (almost) always a stressed syllable, -am is always unstressed.

In EP, stress is very important to the pronunciation of words. In this case, it also becomes important to the way words are spelled, since -ão is usually a stressed syllable and -am is an unstressed syllable.

I won’t talk about this at length – there will be time to actually explain it in depth later on – but it’s important to understand that this difference also affects how vowels in the sentence are pronounced – let’s take a look at cantaram (preterite/pluperfect) vs. cantarão (future):

  • can-TA-ram: the stress makes the A vowel in ta open
  • can-ta-RÃO: the A in ta is closed, and the emphasis is on the last syllable

There are a few cases where -ão is present with nouns (see rule #1) but it’s not the stressed syllable – luckily, you’ll be able to tell that since the stressed vowel takes a diacritic to mark that change in stress (basically, the accent is telling you to override the command that assumes -ão is always stressed the stressed syllable):

  • [a] bênção (blessing): ˈbẽsɐ̃w
  • [o] órfão (orphan): ˈɔrfɐ̃w̃


2 thoughts on “Grammar Tips (#2): ão or am?

  1. edmeyr March 30, 2016 / 3:12 am

    Okay. I planned to make a comment by pressing the blue comment button which didn’t work, but then saw the very tiny print direct the above the line. Could it be any smaller!?

    At any rate, your post took me to my “201 Portuguese verb” book to check out verbs because I noticed that the compilation of -am endings included the “third-person pluperfect” and that it is an identical form with the preterit. I never realized that. It was an excellent idea to group all the tenses that way. It helps to have patterns spelled out as we make our way through so many inflected verbs.



    • luisdomingos April 4, 2016 / 2:51 pm

      Your comment finally saw the light of day! I hope everyone is allowed to make comments freely now (:

      Thank you for your feedback regarding the post – the future and the pluperfect are hardly the most important verbs of the bunch, but it does help to understand the patterns just in case you run into something (or someone) who uses them!

      Good luck with your studies (:


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