Indefinite adjectives and pronouns (tout, chaque, plusieurs)
Summary
Indefinites express totality, quantity, distribution and identity; many come in an adjective form (before a noun) and a matching pronoun form, and several pair with ne for negation.
Explanation
Indefinites are a mixed family of words that quantify or identify without being specific. The crucial distinction is between the adjective use, which accompanies a noun, and the pronoun use, which replaces it. Most learner errors come from mixing the two forms or from getting their agreement wrong, so it helps to learn each word as a pair: adjective form / pronoun form.
Tout is the most versatile and has three roles. As an adjective it agrees in gender and number with its noun: tout le temps, toute la journée, tous les jours, toutes les semaines. As a pronoun it stands alone, usually invariable in the singular (tout va bien, j'ai tout compris) or as tous/toutes for 'all of them' (ils sont tous venus, pronounced with the final -s in tous). As an adverb meaning 'completely', tout is normally invariable (ils sont tout contents) but agrees before a feminine adjective starting with a consonant: elle est toute seule.
Distributives mark 'each' and 'every'. Chaque is the adjective and is always singular and invariable: chaque jour, chaque étudiant. Its pronoun counterpart is chacun (masculine) / chacune (feminine): chacun a son avis, chacune des filles. A common slip is to use chaque on its own as a pronoun; the pronoun must be chacun(e).
Quantity words come in adjective and pronoun pairs too. Quelques (some, a few) is the adjective — quelques amis, quelques minutes — and its pronoun is quelques-uns / quelques-unes: j'en ai vu quelques-uns. Plusieurs (several) is invariable and works as both adjective and pronoun: plusieurs livres, plusieurs sont partis. Certains / certaines (some) likewise functions as adjective (certains jours) and pronoun (certains pensent que…).
Aucun / aucune (no, none) is essentially negative and is used with ne: aucun étudiant n'est venu, je n'en ai vu aucun. It is normally singular. Même is multi-purpose: as an adjective it means 'same' before the noun (le même jour, les mêmes idées) or 'very/-self' after it (le jour même, moi-même); as an adverb it means 'even' (même les enfants comprennent). Autre means 'other' and agrees: un autre livre, d'autres idées, l'un et l'autre.
Finally, the compound indefinite pronouns refer to unspecified people, things or places: quelqu'un (someone), quelque chose (something), quelque part (somewhere), and their negatives personne… ne, rien… ne, nulle part… ne. Note that quelque chose and personne are treated as masculine for adjective agreement (quelque chose de beau, personne n'est parfait), and that an adjective after them is linked with de: quelqu'un d'intelligent, rien de nouveau.
Examples
Tous les jours, tout va bien. — Every day, everything goes well. (tous les jours = adjective (agrees); tout va bien = invariable pronoun.)
Chaque étudiant a un livre, et chacun doit le lire. — Each student has a book, and each one must read it. (Adjective chaque vs. pronoun chacun — never *chaque on its own.)
J'ai plusieurs amis ici, et quelques-uns parlent français. — I have several friends here, and a few of them speak French. (plusieurs (invariable) and the pronoun quelques-uns (adjective would be quelques).)
Aucun train n'est arrivé à l'heure. — No train arrived on time. (aucun is negative and pairs with ne; it stays singular.)
Quelqu'un a dit quelque chose d'intéressant. — Someone said something interesting. (Compound pronouns; adjective linked with de (de + masculine intéressant).)
Nous avons lu le même livre, mais chacun en a tiré une autre leçon. — We read the same book, but each of us drew a different lesson from it. (même (adjective 'same'), chacun (pronoun), autre (agrees: une autre).)
Common mistakes
Elle est venue tout seule et les enfants sont toutes contents.
Elle est venue toute seule et les enfants sont tout contents.
Tout has three uses, and learners often pick the wrong agreement. As an adjective it agrees fully (tous les jours, toute la nuit); as a pronoun it is invariable in tout va bien. The tricky case is the adverb tout meaning 'completely/very', placed before an adjective: it is normally invariable (ils sont tout contents, elle est tout étonnée). The one exception is that, for euphony, the adverb tout does agree before a feminine adjective beginning with a consonant or an aspirate h: elle est toute seule, elles sont toutes honteuses. So the rule reverses the naive expectation — say toute seule (feminine + consonant, agreement) but tout contents (masculine, no agreement) and tout étonnée (feminine + vowel, no agreement).
Prerequisites
Related rules
indefinitesquantifierspronounsagreement