In French the plural articles, and verb agreement show when nouns are plural, yet an ''-s'' is added in spelling.
Singular: Je mange une pomme/Je mange la pomme/La pomme est rouge/La pomme a X.
Plural: Je mange des pommes/Je mange les pommes/La pommes sont rouges/Les pommes ont X.
Is this a prescriptive spelling ''feature'' or addition, or is it historical?
Is the ''-s'' always mute, and purely an orthographic convention, or is it sometimes pronounced on its own and/or able to invoke liaison (as last example sentence)?
If the s is never pronounced, as if it's not even there, then it will help me when reading unfamiliar texts to know that I should just ignore it.