Forming the Plural in Portuguese

In Portuguese, not only nouns are spelled differently according to number (singular/plural), but also words belonging to other word classes such as adjectives, demonstratives, or possessive pronouns.

Thus, learning a few from-singular-to-plural conversion patterns is very helpful in that it helps you navigate the Portuguese word morphology (which is more intricate than other languages such as English).

Consider the singular and plural versions of the following sentence
(the words marked in blue are the words that change form to agree with the number of the noun they refer to. The words marked in red are the nouns themselves):

Singular
A minha querida prima foi ao café com a minha adorada tia .
My dear cousin went to the coffee house with my adored aunt.

Plural
As minhas queridas primas foram ao café com as minhas adoradas tias.
My dear cousins went to the coffee house with my adored aunts.

As it stands out above, Portuguese has a more varied word morphology to accommodate changes in number (singular/plural) than English. This is a challenge for language learners as they need to keep sentences number-aligned to make them look and sound right.

Luckily, there are a few conversion patterns that will make it easier. Read on.

Gender and number go hand-in-hand and you may want to read this as well:  Gender of Portuguese Words: A Guide to Masculine-to-Feminine Spelling Patterns.

Nouns –  singular-to-plural conversion patterns

S-plural

In Portuguese, just as in English, the s-plural is dominant. Accordingly, nouns ending in any vowel – -a, -e, -i, -o, -u (the nasal vowel -ã included) – form their plural by adding an -s at the end. A few examples:

SINGULAR	PLURAL
o cabelo (hair)	os cabelos (hairs)
a perna (leg)	as pernas (legs)
a maçã (apple)	as maçãs (apples)
o dente (tooth)	os dentes (teeth)
o rei (king)	os reis (kings / king and queen)
o pau (stick)	os paus (sticks)
. . .

eS-plural

This is a variation of the s-plural. Nouns ending with the consonants -n, -r, -s, and -z form their plural with -es. A few examples: