Acordo Ortográfico (Spelling Reform)

The Acordo Ortográfico de 1990 — universally referred to as AO90 — is the spelling reform that reshaped how Portuguese is written in the 21st century. Signed in 1990 by representatives of the eight Portuguese-speaking countries, it became official in Portugal in 2009 and fully mandatory in 2015. Today, every Portuguese newspaper, every government document, every textbook published in PT-PT follows the AO90 spelling rules. Pre-AO90 spellings persist in older books, in some literary writing by authors who object to the reform, and in any text predating the changeover, but they are no longer the norm.

For learners of European Portuguese, AO90 matters in three ways. First, it determines which spelling you write in your own production — and that is the AO90 spelling, end of story. Second, it tells you how to read modern texts and recognise the principles behind apparently odd-looking words like ato (act, action) or receção (reception). Third, it gives you the framework for reading pre-AO90 texts — anything published before about 2010, or republished from older editions — where you will encounter the older spellings and need to know they are simply pre-reform variants of words you already know.

This page is the systematic reference. We cover the background to the reform, then walk through each category of change, with before/after tables and examples. Where AO90 introduced double spellings (where two forms are tolerated because the underlying pronunciation differs across varieties), we flag them.

Background: why a reform?

The Portuguese-speaking world had been operating under two different spelling systems since the early 20th century. Portugal codified its modern spelling in 1911 (the Reforma Ortográfica de 1911), and Brazil followed with its own conventions. Several attempts at unification followed — the Acordo Ortográfico Luso-Brasileiro de 1945 (mostly adopted by Portugal but not by Brazil), the Acordo Ortográfico de 1971 (Brazil), and the Acordo Ortográfico de 1973 (Portugal) — but the two systems remained meaningfully different in spelling.

By the 1980s, the Lusophone community recognised that diverging orthographies were impractical for international communication, education, and publishing. The 1990 agreement — signed by Portugal, Brazil, Angola, Mozambique, Cape Verde, Guinea-Bissau, São Tomé and Príncipe, and (later) East Timor — aimed to unify spelling while acknowledging that the two main varieties (PT-PT and PT-BR) had genuinely different pronunciations that the spelling should reflect.

The agreement took years to ratify. Brazil implemented it in 2009. Portugal's transition began in 2009 (effective in education and government), with a six-year grace period ending in 2015. Today AO90 is the only official spelling in PT-PT — though, as we shall see, a number of academics, authors, and ordinary speakers continue to use pre-AO90 forms in personal writing and in deliberate political resistance.

Change 1: Silent consonants dropped

The single most visible AO90 change in PT-PT is the dropping of silent consonants in many Latinate words. Before AO90, PT-PT preserved consonants like c, p, b in words where they were no longer pronounced — they were carried over from the Latin originals as etymological markers. AO90 reasoned that, if a consonant is silent, there is no pedagogical reason to write it.

The pattern

The dropped consonants are mostly c and p before another consonant in clusters like -ct-, -pç-, -pt-, -pç-. The general rule of AO90: drop the silent letter from spelling in PT-PT.

The crucial caveat: pronounced consonants kept

AO90 follows a principle of pronunciation: a consonant is dropped only when it is genuinely silent. Letters that are still pronounced — even if they are silent in PT-BR — are kept in PT-PT.

The most famous case: facto (fact) keeps its c in PT-PT because the c is genuinely audible: /'faktu/. The PT-BR spelling is fato. Similarly, contacto (contact) is the PT-PT form (with audible c), against PT-BR contato.

Double spellings

Where pronunciation varies even within PT-PT, AO90 admits double spellings — both forms are correct. Examples:

• receção / recepção — AO90 prescribes receção (the p dropped) as the PT-PT default; recepção remains current in PT-BR.
• aspeto / aspecto — aspeto is the PT-PT AO90 default; aspecto is kept in PT-BR.
• conceção / concepção — conceção (PT-PT AO90) vs concepção (PT-BR).

Modern PT-PT publications follow the AO90 default (no silent consonant), but the double-spelling provision means a speaker who pronounces the p in recepção can write it that way without being wrong.

Words sometimes confused with double spellings

A handful of pre-AO90 spellings have produced ongoing controversy. Egipto (Egypt) was contested: pre-AO90 spelling kept the p; AO90 dropped it (Egito); PT-PT speakers and publishers vary. Similarly peremptório/peremtório (peremptory). For the purposes of this page, the safe rule is: in modern writing, follow AO90; if you encounter the pre-AO90 spelling in older texts, simply recognise it as the older form.

Change 2: Accent marks dropped from certain homographs

Pre-AO90 spelling used differential accents — accent marks whose only function was to distinguish two words that would otherwise be spelled identically. AO90 dropped many of these, on the grounds that context disambiguates. The change is small in scope but visible.

Differential accents retained

A few differential accents were preserved because the alternative would create real ambiguity in tense or meaning. The most important is pôde (he was able to — preterite) keeping its circumflex to distinguish from present pode (he can).

Third-person plural verb forms lost the circumflex

A small set of verbs in -ver, -ler, -crer, -dar used to carry circumflex on the doubled vowel of the 3rd-person plural:

Acute on -eia words

Some PT-BR pre-AO90 spellings used acute on -eia words: idéia, assembléia, jibóia, herói, heróico. Most of these had already lost the accent in PT-PT decades earlier (PT-PT writes ideia, assembleia, jiboia); for those PT-PT readers, AO90 was a non-change. Herói and heróico are exceptions kept by PT-PT (the ó is genuinely open and stressed).

PT-PT vs PT-BR variant accents

A few words have different accent forms in PT-PT and PT-BR because the pronunciation differs. AO90 explicitly preserved these variants:

These differences reflect genuine pronunciation variation. PT-PT speakers say António with an open /ɔ/ (acute); PT-BR speakers say Antônio with a closed /o/ (circumflex). Both spellings are correct in their respective varieties.

Change 3: Hyphenation simplified

AO90 rationalised the rules for hyphenation of prefixed and compound words. The general principle: hyphen when the prefix-final letter equals the stem-initial letter (vowel meeting same vowel), or when the stem begins with h. Solid otherwise — sometimes with consonant doubling.

The major changes affect auto-, contra-, anti-, super-, sub-, semi-, hiper-, micro-, neo-, pseudo-, ultra- and a few others, plus the family of co-, re-, pré-, pós-. The full rules are at Common Prefixes; here are the AO90 highlights:

Pre-AO90 vs AO90 hyphen examples

Hyphens kept

Some hyphens are preserved by AO90:

• Before h: anti-herói, super-herói, co-herdeiro (in some legal contexts), sub-humano, semi-humano.
• Before vowel = same as prefix-final: contra-ataque, micro-ondas, anti-inflamatório, semi-intensivo, auto-observação.
• Permanent prefixes: ex- always (ex-presidente, ex-marido, ex-namorada), pós- always (pós-graduação, pós-parto), pré- always when stressed (pré-histórico, pré-aviso), vice- always (vice-presidente), recém- always (recém-nascido), sem- always (sem-abrigo).

Compound words: hyphens dropped from common compounds

AO90 simplified some everyday compound nouns by removing the hyphens. The most-cited example:

• Pre-AO90: fim-de-semana
• AO90: fim de semana

Other examples:

• Pre-AO90: dia-a-dia → AO90: dia a dia
• Pre-AO90: chá-da-tarde → AO90: chá da tarde
• Pre-AO90: moto-quatro → AO90: motoquatro or moto-quatro depending on use

But many compounds keep their hyphens because they form a single noun:

• guarda-chuva (umbrella)
• guarda-redes (goalkeeper)
• para-quedas (parachute)
• segunda-feira (Monday) and other day-names
• primeiro-ministro (prime minister)

Change 4: Capitalisation rules

AO90 also brought changes to capitalisation, mostly toward lowercasing what English speakers might expect to see capitalised.

Months and days now lowercase

Pre-AO90, PT-PT often capitalised month names and sometimes weekday names (a French-style convention). AO90 makes them lowercase across the board.

• Pre-AO90: Janeiro, Fevereiro, Segunda-feira, Domingo
• AO90: janeiro, fevereiro, segunda-feira, domingo

Cardinal directions lowercase except in proper names

• o norte de Portugal — lowercase
• o sul — lowercase
• América do Norte — capitalised because it is a proper name

Titles of works

For book, film, and painting titles, AO90 prescribes capitalising only the first letter and proper nouns within the title, lowercasing the rest.

• Pre-AO90: Os Maias, O Guarani
• AO90: Os Maias (kept, because Maias is a proper name) → Os maias (debated)

In practice, this rule is inconsistently applied. Many publishers, including major Portuguese houses, continue to capitalise main words in titles. The AO90 prescription is sometimes overridden by editorial style.

Nationalities, religions, languages: lowercase

These have always been lowercase in PT-PT (unlike English): português, francês, católico, judeu, islâmico. AO90 confirms this.

Change 5: Other minor simplifications

K, W, Y officially in the alphabet

Pre-AO90, the Portuguese alphabet had 23 letters; k, w, y were "foreign letters" used only in loanwords. AO90 brings the alphabet to 26 letters, with k, w, y fully integrated. In practice, however, those letters still appear almost exclusively in loanwords and proper names — Portuguese vocabulary mostly avoids them.

Trema (¨) abolished

The trema was the diacritic used over a pronounced u in qu/gu combinations: lingüiça (showing that u is pronounced /lĩ'gwisɐ/). PT-PT had already abolished the trema in 1945, so this was a non-change for PT-PT speakers. PT-BR adopted the abolition in 1990.

In modern PT-PT, you must learn from each word whether the u in qu/gu before e/i is silent (queijo, guerra) or pronounced (quotidiano, freqüência → modern frequência).

Some compound words restructured

AO90 simplified or restructured a handful of compound words. Fim-de-semana → fim de semana is the most-cited; smaller examples include à-vontade → à vontade (when used as an adverbial), cor-de-rosa → cor-de-rosa (kept), and some technical terms.

Continuing PT-PT vs PT-BR differences

Despite AO90's harmonising goal, several spelling differences between PT-PT and PT-BR remain because they reflect genuine pronunciation differences.

The principle is consistent: where a letter is genuinely pronounced in one variety and silent in the other, the spelling reflects that. This is now one of the few visible spelling distinctions between PT-PT and PT-BR.

Reading older texts

Any PT-PT text from before about 2009 was written in pre-AO90 spelling. Books from the 1990s and early 2000s, periodicals from before 2009, and reprints of older works will use the older spellings. The differences are systematic and you can re-recognise them quickly:

• acção, projecto, recepção, actor, director, óptimo (older forms) → ação, projeto, receção, ator, diretor, ótimo (modern).
• vêem, lêem, dêem → veem, leem, deem.
• pára (verb) → para; pêlo (fur) → pelo.
• fim-de-semana → fim de semana.
• Janeiro → janeiro.

A handful of literary authors and academic conservatives continue to use pre-AO90 spellings in their personal writing, viewing the reform as a political imposition that compromises etymology. José Saramago famously refused to use AO90; his pre-2010 works are in pre-reform spelling, his last novels were published in both versions. This is a minority position in the publishing industry — most modern PT-PT publications use AO90.

Reception of AO90

The reform has been controversial in Portugal. Supporters argue it harmonises the Lusophone spelling system and removes etymological deadwood from the spelling. Opponents argue:

• It pushes PT-PT toward PT-BR conventions in ways that obscure the genuine PT-PT pronunciation (recepção with audible p becoming receção).
• It eliminates etymological information that helps with reading Latin and Romance cognates.
• It creates ambiguities (pára / para both spelled para, etc.).
• It was politically imposed without sufficient consultation with linguists.

Some Portuguese authors, journalists, and academics have refused to adopt it. The newspaper Público used pre-AO90 spelling well into the 2010s. Several major publishing houses publish in both spellings depending on the author's preference.

For learners, the practical advice is unchanged: use AO90 in your own writing, since that is the official spelling and the form taught in modern textbooks. Be prepared to read pre-AO90 spellings in older books, in some literary writing, and in any text predating 2010.

Practical advice for learners

Three rules of thumb:

1. Write AO90. Modern PT-PT writing uses AO90 spellings. Use ação, projeto, receção, ator, diretor — not the pre-2009 forms.
2. Read both. When you encounter pre-AO90 spellings (acção, projecto, vêem), recognise them as older variants and translate them to AO90 forms in your mental dictionary.
3. Don't confuse PT-PT with PT-BR. AO90 reduced the PT-PT vs PT-BR spelling differences, but did not eliminate them. Facto (PT-PT) ≠ fato (PT-BR); António (PT-PT) ≠ Antônio (PT-BR). These are PT-PT specifics, not pre-AO90 leftovers.

Common mistakes

Key takeaways

• AO90 is the spelling reform that became official in PT in 2009 and mandatory in 2015. It is the current standard.
• The four major changes: silent consonants dropped (acção → ação); some differential accents dropped (pára → para); third-person plural circumflex dropped (vêem → veem); hyphenation simplified.
• Pronounced consonants kept: facto, contacto, impacto keep the c in PT-PT because the c is genuinely audible — these are PT-PT specifics, distinct from PT-BR.
• Lowercasing: months, days of the week, seasons, cardinal directions (when not in proper names), nationalities, languages.
• Hyphenation: solid for most prefixes (autoestrada, antifascista, coautor); hyphen before h or before same vowel (anti-herói, contra-ataque).
• Trema abolished (PT had already abolished it in 1945; AO90 codified this for PT-BR too).
• K, W, Y officially in the alphabet under AO90 (still mostly limited to loanwords).
• Pre-AO90 vs PT-BR: distinct categories. Pre-AO90 PT-PT (acção, projecto) is older spelling, replaced by AO90; PT-BR (fato, recepção, Antônio) is a separate variety with stable spelling differences from PT-PT.
• In your own writing: use AO90. In reading older texts: recognise pre-AO90 forms. Both spellings are mutually intelligible; no Portuguese speaker is confused by either.
• AO90 has been controversial in Portugal; some authors and publishers continue to use pre-AO90 spellings in personal writing. The standard for textbooks, government, and journalism is AO90.