Brazilian Portuguese Grammar

Rules of accentuation

The use of accent marks

6. Monosyllables ending in -a, -as, -e, -es, -o and -os must get an accute accent (open vowels) or a circumflex accent (closed vowels):

Oral diphthongs	Portuguese	English
-a	pá	shovel
-as	más	bad
-e	pé	foot
-es	três	three
-o	pó	dust
-os	nós	knots

7. Monosyllabic object pronouns, reflexive pronouns, prepositions, definite and indefinite articles, conjunctions, combinations, contractions and the relative pronouns que don't get accent marks:

Word class	Portuguese (English)
object pronouns	o (him, it)
	os (them)
	a (her, it)
	as (them)
	lhe (him, her, it)
	lhes (them)
	me (me)
	te (you)
	nos (us)
	*vos (you plural)*

reflexive pronouns	me (myself)
	te (yourself)
	se (himself, herself, itself, oneself, yourself, yourselves, themselves)
	nos (ourselves)
	vos (yourselves)

definite articles	o (the)
	os (the)
	a (the)
	as (the)

indefinite articles	um (a, an)
	uns (some)
	uma (a, an)
	umas (some)

prepositions	por (for)
	de (of)
	com (with)
	sem (without)
	sob (under)
	em (in, on, at)