Most adjectives ending in -al change to -aux (masculine plural) or -ales (feminine plural) - see Forming the plural of adjectives ending in -al - but there are exceptions to that rule.
Look at these cases:
Ces tabourets sont bancals.
These stools are wobbly.
The following adjectives are exceptions which take -s in the masculine plural form:
| Masculine singular | Masculine plural | English |
| banal | banals | banal / ordinary |
| bancal | bancals | wobbly / rickety |
| fatal | fatals | fatal / lethal |
| naval | navals | naval |
| natal | natals | natal |
| glacial | glacials / glaciaux | freezing |
| final | finals / finaux | final |
ATTENTION:
Both plural forms of glacial and final are accepted in French: regular (glaciaux / finaux) and irregular (glacials / finals)
Il y a des vents glacials aujourd'hui!
There are some freezing winds today!
Les derniers jours ont été glaciaux !
The last days have been freezing !
See also Forming the plural of nouns ending in -al
Examples and resources
Il y a des vents glacials aujourd'hui!
There are some freezing winds today!
Ces serpents sont particulièrement fatals.
These snakes are particularly deadly.
J'adore les défilés navals!
I love naval parades!
Les derniers jours ont été glaciaux !
The last days have been freezing !
Ces tabourets sont bancals.
These stools are wobbly.
J'ai reçu mes résultats finals.
I got my final results.
Ce sont des gens banals.
These are ordinary people.
J'ai reçu mes résultats finaux.
I got my final results.
Q&A
Aurélie
Kwiziq language super star
13/06/16
Yes that's correct, both spellings are perfectly acceptable and interchangeable.
Susan
Kwiziq community member
14/05/17
Gary
Kwiziq community member
1/02/18
Aurélie
Kwiziq language super star
1/02/18
I've looked through all our questions, and they all accept glaciaux as a correct alternate answer.
Do you have the specific question in mind by any chance?
Merci et à bientôt !
engenious
Kwiziq community member
2 February 2018
1 reply
Banals/Banaux
Is this pair also interchangeable? This test question suggest otherwise: Which one of these plural forms is wrong? : géniaux, banaux, généraux, totaux
Chris
Kwiziq community member
2 February 2018
2/02/18
.....except in the very rare case when the adjective "banal" us used in its other meaning: feudal (as in the "feudal system"). In that case the plural masculin is "banaux": "les moulins banaux" = the feudal mills where peasants could mill their grain paying a fraction of it to the lord of the land.
-- Chris (not a native speaker).