What is the background of having rules for marking the accentuated syllables in Portuguese? For example the word "tecnológica" is a proparoxytone, and all of these words must have a graphic accent on the stressed syllable; while "mesa" has no graphic accent because paroxytone words ending in "a" don't have it.

So, how Latin in Portugual evolved to have such a complex system for writting these graphic accents or even for having accentuation marks at all? Since it's common for I.E. languages to have a stressed syllable, but not for having marks or rules for when to graphically represent the stress.

I know Spanish has a (simpler) system and so does Italian; I believe French to be a bit more obscure in this sense. Also, I know Latin had marks to indicate long vowels, but do portuguese accent marks come from there?

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    Are you asking what features of Portuguese make these accent marks necessary, or why this particular system ended up being used in Portuguese (as opposed to e.g. English where stress is unpredictable but we just don't mark it)?
    – Draconis
    May 4, 2023 at 21:00
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    Please write your question in the form of a question. This will clarify what you are asking about. May 4, 2023 at 21:25
  • @Draconis, the second, but if you have any hint on the first, it would be nice to know too. May 5, 2023 at 10:46
  • [Questions in English: How did or how does [main verb: How did Latin evolve in Portugal etc.] For your information, we say accent marks in English. Also, please go look where where the stress falls in Portuguese. This proparoxítona in English is stress on third-from-the-last syllable.
    – Lambie
    May 10, 2023 at 13:40

2 Answers 2


It is true that the earliest fragments of Galician-Portuguese have no stress marking, although they already make use of other diacritics such as the tilde and the cedilla. The first Portuguese grammar, the 1536 Grammatica da lingoagem portuguesa by Fernão de Oliveira, had no stress marking at all. Yet, only a few years later, in 1540, the Gramática da Língua Portuguesa by João de Barros was published, with its italic typeface, its sharp s, and its use of the acute accent to mark stress, notably in the third person singular of the future indicative (e.g. amará) to distinguish it from the same in the pluperfect indicative (amara). He also shows the understanding that the phonemes /ɐ/, /ɛ/, /ɔ/ are separate from /a/, /e/, /o/, which was nascent in previous work; he proposes to use the Greek letters alpha, epsilon and omega for the first set, similar what had been proposed by Trissino in 1524 in the Ɛpistola del Trissino de le lettere nuωvamente aggiunte ne la lingua Italiana. However, in practice we see the use of the acute accent where the vowel is stressed but in the former set.

All this has to be contextualised against the backdrop of printed orthography in Renaissance Europe, and especially with the influence of the polytonic diacritics of Classical Greek: acute, grave and circumflex. Already extant in manuscripts of the Bible in Greek, stress accent marks had been adopted by the Aldine Press in Venice systematically from 1505, although they were not the first to use them in Italy. During the 1520s in France, written accent marks were employed to qualify the quality of the vowel, which was linked to vowel length in Middle French rather than to the stress accent; notable among these French printers was Robert Estienne. It was in the 1550s that the graphical stress accent diacritic came to Spanish, although a mix of grave, acute and circumflex were used for reasons of disambiguation and grammar.

A little later, the Orthographia da lingoa portuguesa from 1576 by Duarte Nunes do Leão consistently uses the acute and the circumflex accents for stress where it disambiguates:

Soomente deuemos accentuar as dições, em que pode hauer differença de significação, quando teem differente accento, como, côr, por color, que screueremos com accento circumflexo, & cór por vontade com agudo.

We see how the grave accent is given basically no place in Portuguese orthography; this becomes the mainstream orthography through the 16th and 17th centuries, although the use of the acute-vs-circumflex fluctuates somewhat. E.g. Vera 1631 uses the circumflex on the final stressed vowel in the future tense verbs, giving e.g. amarâ compared with amára for the pluperfect.

Into the 18th century, with the 1734 Orthographia by Madureira Feijó, cements the position of acute as the more "open" vowels, and the circumflex the more "closed" when in stressed position. He does also incorporate the metaphony of the singular-plural and masculine-feminine alternations, thus ôlho but ólhos; this is not retained in the current orthography.

  • Did you mean to put the acute on pór and not cor at the end of the quote? I had to read it three times to make it make sense (by realising that it only makes sense if the acute is on cór instead). May 10, 2023 at 1:07
  • @JanusBahsJacquet Thank you!
    – Michaelyus
    May 10, 2023 at 8:27
  • That was awesome. Thanks a lot! May 10, 2023 at 11:21
  • I noted that the "Gramática da Língua Portuguesa by João de Barros" there's a lot of ę as in "molhęr". It seems like it's a replacement for an open "e" but he also uses an "ɛ" for that same purpose. You know what that was supposed to be? May 10, 2023 at 11:29
  • I see that de Barros (or his Lisbon-based printer!) does not use "é" at all, using "ę" instead, though he does use both "á" and "ó".
    – Michaelyus
    May 11, 2023 at 9:01

The accentuation system in the orthography of Portuguese was created to be logic, so that every word shows where the stressed syllable is in the most economic way, making only a relatively small number of words accentuated.

Proparoxytones are the rarest words in portuguese, so all of them are accentuated. Paroxytones are the most common, so in all common endings, such as a(s), o(s), e(s) and em/ens they are not accentuated, and that already leaves a huge amount of words without accents. To complete that, all words with other endings and that have no graphic accent are deductively oxytones, leaving a whole bunch of other words without an accent and still showing where the tonicity is. It is quite smart.

If it uses the circumflex or an accute accet depends on the quality of the vowel, if it is more closed, the circumflex is used (â, ê, ô) and if it is more open, the acute accent is used (á, é, ó) — í and ú are used just to show tonicity.

This system we use today is recent, the latest "update", was made a few years ago in the last reform and it is adopted in every Portuguese-speaking country.

The whole diacritic thing started a long time ago. The tilde (ã, õ...), for instance, was invented during the Middle Ages to represent the nasalization of vowels, in fact it was originally a superscprit little N, the letter that represents the very sound that disappeared and left the nasal trace in the vowel during the evolution of the language. The cedilla (ç) originated from a small subscript Z. These were created to write the new sounds that emerged in the evolution, because there was no way to write them with the roman alphabet.

The grave accent (à) is used nowadays only when there is crasis, not to change the quality or show accentuation.

Portuguese makes a really good use of its five diacritics.

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    Perhaps worth including that a tilde also indicates stress like circumflexes and acutes, except if there is also a circumflex or acute on a different syllable, in which case that takes priority. May 9, 2023 at 2:52
  • Thanks a lot for you explanation. Now, is there any record of its first usage or how it came to be necessary? May 9, 2023 at 11:13
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    @Bernardo It’s not ‘necessary’ as such. Other languages – like English – do all right without it. It’s makes it easier to read Portuguese and makes the spelling system more unambiguous, but it could be done away with without any serious negative impact. May 9, 2023 at 11:40
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    Well, one could argue that it was "always necessary", because since Portuguese was what we call Galician-Portuguese in the Middle Ages there were already proparoxytones, paroxytones and oxytones, but they didn't need to do that, they new the words, they were native speakers. But as orthography was being refined and becoming easier for those who didn't know specific words to pronounce them correctly (and also to foreign people), it was gradually reaching what we have now. Portuguese had a whole other orthography in the beginning of the last century, very latinized. May 9, 2023 at 11:47

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