The formation of the plural in Spanish follows a basic rule which consists of adding an -s to the end of the word:

casa – casas (house)

gato – gatos (cat)

Nevertheless, there are words which, due to their formation, follow other rules for plurals in Spanish. We are talking about the words ending in -s, -y or -z. Continue reading to learn them.

Plurals of Words Ending in S or X

The rules for forming the plurals depend on the length of the word:

1. If the word is monosyllabic or polysyllabic but acute, add -es:

vals – valses (waltz)

inglés – ingleses (English)

2. If it is not a polysyllabic acute word, the plural is invariable:

crisis – crisis (crisis)

pasapurés – pasapurés (food processor)

Rule for Plurals Ending in Y

Words ending in -y are very frequent in Spanish. There are 3 rules of the plural in Spanish for these kinds of words:

1. If -y is preceded by a vowel, the plural is formed by adding -es. Here, you can see that the -y performes the role of a consonant:

buey – bueyes (ox)

ley – leyes (law)

2. There is, of course, one exception. These are the foreign words that we have incorporated into the Spanish vocabulary repertoire. For these words, we transform the -y into -i and add the -s at the end as the -y remains as a vowel:

jersey – jerséis (jumper)

gay – gais (gay)

3. Today is your lucky day! There are some words that allow the formation of both plurals, so there is no possibility for you to be mistaken:

guirigay – guirigáis/guirigayes (noise, chaos)

estay – estáis/estayes (backstay)

What happens if the -y is preceded by a consonant? These are foreign words that do have an adapted spelling in Spanish, so their plural formation follows the basic rules of the plural in Spanish:

dandi – dandis (dandy)

ferri – ferris (ferry)

Plural of Words Ending in Z

1. If the -z is preceded by a vowel, it changes to -c and -es is added:

cáliz – cálices (goblet)

2. Foreign words also follow the same rule (so this is an easy one!):

interfaz – interfaces (interface)

The RAE and the Basic Rules for Forming the Plurals

The rules for forming the plurals are clear and concise, the only thing you have to do is to learn them so that you never make a mistake. As always, the best way to know them is to check the RAE channels.      Another way to cultivate yourself is to write non-stop in a Spanish spelling and grammar checker to learn in real time while you practice. iScribo is here to help you, have you tried it yet? Which words are more difficult for you when it comes to practising the formation of the plural in Spanish? Let us know in the comments.