When an adjective modifies a plural noun, an s should be is added to the end however this s is never pronounced.

Whenever an adjective describes both a male and female noun, the masculine form is used.

Monsieur Martin et sa femme sont gentils.
Mr Martin and his wife are nice.

Normally adjectives follow the noun they modify, however this isn't the case for all adjectives.

Sometimes the meaning of an adjective changes depending on it's placement.

The following adjectives are all irregular. The archaic masculine form is now only used in front of masculine nouns that begin with a vowel or silent h.