In Portuguese grammar, nouns, adjectives, pronouns, and articles are moderately inflected: there are two genders (masculine and feminine) and two numbers (singular and plural).
It has a number of grammatical features that distinguish it from most other Romance languages, such as a synthetic pluperfect, a future subjunctive tense, the inflected infinitive, and a present perfect with an iterative sense.
Like most Indo-European languages, including English, Portuguese classifies most of its lexicon into four word classes: verbs, nouns, adjectives, and adverbs.
Frequently in oral language, and occasionally in writing, these words are followed by the interrogative device é que (literally, "is [it] that"; compare French est-ce que in wh-questions).
In both versions of Portuguese, emphasis can also result from syntactical processes that are not restricted to answers, such as the addition of adverbs like muito ("much") or muitíssimo ("very much").
Adjectives and determiners (articles, demonstratives, possessives, and quantifiers) must be inflected to agree with the noun in gender and number.
Portuguese does not inflect nouns to indicate their grammatical function or case, relying instead on the use of prepositions (simple and phrasal), on pleonastic objects, or on the context or word order.
Grammatical gender of inanimate entities is sometimes different from that used in sister languages: thus, for example, Portuguese árvore ("tree") and flor ("flower") are feminine, while Spanish árbol and Italian fiore are masculine; Portuguese mar ("sea") and mapa ("map") are masculine, while French mer and carte are feminine.
In many cases, the gender and number of a noun can be deduced from its ending: the basic pattern is "-o" / "-os" for masculine singular and plural, "-a" / "-as" for feminine.
So, casa ("house"), mala ("suitcase"), pedra ("stone"), and inteligência ("intelligence") are feminine, while carro ("car"), saco ("bag"), tijolo ("brick"), and aborrecimento ("annoyance") are masculine.
However, the complete rules are quite complex: for instance, nouns ending in -ção are usually feminine, except for augmentatives like bração ("big arm").
For words ending in other letters, there are few rules: flor ("flower"), gente ("folk"), nau ("ship"), maré ("tide") are feminine, while amor ("love"), pente ("comb"), pau ("stick"), café ("coffee") are masculine.
On the other hand, the gender of some nouns, as well as of first- and second-person pronouns, is determined semantically by the sex or gender of the referent: aquela estudante é nova, mas aquele estudante é velho ("this (female) student is new, but that (male) student is old"; or eu sou brasileiro ("I am Brazilian", said by a man) and eu sou brasileira (the same, said by a woman).
Possible endings other than -inho(a) are:-ito(a), e.g. copo/copito ("glass") -ico(a), e.g. burro/burrico ("donkey") -(z)ete, e.g. palácio/palacete ("palace") -ote, e.g. saia/saiote ("skirt") -oto, e.g. lebre/lebroto ("hare/leveret") -ejo, e.g. lugar/lugarejo ("place") -acho, e.g. rio/riacho ("river") -ola, e.g. aldeia/aldeola ("village") -el, e.g. corda/cordel ("rope")
Most adjectives have—in addition to their positive, comparative, and superlative forms—a so-called "absolute superlative" form (sometimes called "elative"), which enhances the meaning of the adjective without explicitly comparing it (lindo, "beautiful"; muito lindo or lindíssimo, "very beautiful"), it can appear in both analytic or synthetic form.
Thus: Unlike Spanish, an orthographic accent on the adjective is not retained on the adverb; thus for example rápido → rapidamente ("fast, quickly").
The English concept of phrasal verb—a verb-and-adverb sequence that forms a single semantic unit, such as "set up", "get by", "pick out", etc.—is rare in Portuguese.
The grave accent in à / às has phonetic value in Portugal and African countries, but not in Brazil (see Portuguese phonology).
The prepositions de and em form contractions with the third-person pronouns, as, for example, dele ("of him, his"), nelas ("in them [fem.
: Just like the articles, they form contractions with certain preceding prepositions Portuguese verbs are usually inflected to agree with the subject's grammatical person (with three values, 1 = I/we, 2 = thou/you, 3 = he/she/it/they) and grammatical number (singular or plural), and to express various attributes of the action, such as time (past, present, future); aspect (completed, interrupted, or continuing); subordination and conditionality; command; and more.
Ser is used with adjectives of fundamental belief (Não sou católico, "I'm not Catholic"), nationality (És português, "You are Portuguese"), sex/gender (É homem, "He's a man"), intelligence (Somos espertos, "We are smart"), etc.
Many of its uses would be translated into English by the "-ing" nominal form, e.g. mesa para cortar ("cutting table"), cantar é bom ("singing is good"), trabalhe sem parar ("work without pausing").
European Portuguese has the distinct feature of preferentially using the infinitive preceded by the preposition "a" in place of the gerund as the typical method of describing continuing action: The gerund "-ndo" form is still correct in European Portuguese and it is used colloquially in the Alentejo region, but relatively rare (although its adverbial uses and the other participle forms are not uncommon).
On the other hand, the "a + infinitive" form is virtually nonexistent in Brazil, and is considered incorrect in Brazilian Portuguese, though it can be found in 19th century literature.
Some of the most frequent verbs are among the most irregular, including the auxiliaries ser ("to be"), haver ("there to be" or "to have"), ter ("to possess", "to have", "there to be" – in Brazilian Portuguese), ir ("to go").
Grammarians usually classify the verbal inflections (i.e. the synthetic verb forms) into the following moods, tenses, and non-finite forms: The conditional tense is usually called "future of the past" in Brazilian grammars, whereas in Portugal it is usually classified as a separate "conditional mood".
In Brazil, they are used nearly exclusively in the printed language, though even in that environment the -ra synthetic pluperfect has been losing ground to the compound form using tinha in the last decades.
However, in European Portuguese an alternative construction has appeared, formed with the preposition a followed by the infinitive of the main verb: e.g. Eu estou a trabalhar.
Tenses with multiple auxiliaries: An active clause with a transitive verb and direct object can be transformed into a passive clause much the same as is done in English: the original object becomes the subject; the verb is replaced by ser (in the same mood and tense) followed by the past participle of the original verb; and the original subject may become an adverbial complement with the preposition por ("by"): As in Spanish, there is also—for third-person objects, and when the agent is not expressed—a "reflexive" passive, which uses the pronoun se: The same construction extends to some intransitive verbs, in which case they are rendered "impersonal", in the sense that their subject is not expressed: The Portuguese subjunctive mood is used mainly in certain kinds of subordinate clauses.
On the other hand, those pairs of words were eventually generalized by Portuguese speakers into a derivational rule, that is somewhat irregular and defective but still productive.