Future tense

English says when I arrive and leaves that clause in the present. French marks both halves as future: quand j'arriverai, je t'appellerai. The same applies after lorsque, dès que and aussitôt que. Writing quand j'arrive for a future event is the classic English-speaker slip.

Take the whole infinitive and add -ai, -as, -a, -ons, -ez, -ont: je parlerai, tu finiras, nous partirons. Verbs in -re drop their final e first: prendre gives je prendrai. For everyday plans, aller plus an infinitive does the same job: je vais partir.

About fifteen common verbs have their own future stem: être ser-, avoir aur-, aller ir-, faire fer-, pouvoir pourr-, voir verr-, venir viendr-. The endings never change, so je serai, tu auras, nous irons. Every stem ends in r, and the conditional uses the same ones.