Savoir (to know) · All tenses

Savoir = to know facts, information, or how to do something ('je sais la réponse', 'je sais nager'). Connaître = to know by familiarity (people, places, things): 'je connais Paul' (I know Paul), 'je connais Paris' (I know Paris). Mixing them is one of the top-3 French learner confusion points. Rule of thumb: if you can state it, it's savoir; if you can experience it, it's connaître.

'Savoir + infinitive' = 'to know how to + verb': 'je sais nager' (I know how to swim), 'tu sais conduire?' (do you know how to drive?). This is the standard French way to express acquired skills. NOTE: 'pouvoir + infinitive' means 'to be able to + verb' (physical/situational ability): 'je peux nager' (I can swim — right now). Use savoir for the skill itself; pouvoir for current ability.

Use avoir + the past participle 'su': j'ai su, tu as su, il a su, nous avons su, vous avez su, ils ont su.

Savoir is one of French's meaning-shift preterite verbs (alongside connaître, pouvoir, vouloir, devoir). The imparfait 'je savais' keeps the static meaning ('I knew already'); the passé composé 'j'ai su' marks the moment of finding out ('I came to know'). Same shift as Spanish 'supe' vs 'sabía'. The pedagogy point: 'j'ai su' is the moment of acquisition; 'je savais' is the state of knowing.

Use 'j'ai su' for the moment of finding out: 'j'ai su la nouvelle ce matin' (I found out the news this morning). Use 'je savais' for ongoing past knowledge: 'je savais déjà la nouvelle' (I already knew the news). The contrast is acquisition (passé composé) vs static knowing (imparfait).

Savoir is regular in the imparfait: je savais, tu savais, il/elle/on savait, nous savions, vous saviez, ils/elles savaient. Stem 'sav-' from the nous form 'savons'.

Use 'je savais' for ongoing past knowledge — what you already knew during some past stretch of time: 'en 2020, je savais déjà' (in 2020, I already knew). Use 'j'ai su' for the moment of finding out: 'j'ai su la nouvelle en 2020' (I found out the news in 2020). The contrast is static knowledge (imparfait) vs acquisition (passé composé).

No — savoir is fully regular in the imparfait. Despite its many other irregularities (sais, sache, saurai), the -ais endings attach cleanly to the stem 'sav-'. Only three French verbs have irregular imparfaits: être (j'étais), aller (allais — but the stem 'all-' itself comes from the nous form normally), and avoir (avais — also regular from 'avons'). Actually only ÊTRE is fully irregular here. Savoir conforms.

The subjonctif of savoir is: que je sache, que tu saches, qu'il sache, que nous sachions, que vous sachiez, qu'ils sachent. The stem 'sach-' is fully irregular and used across all persons — no stem split.

Savoir's subjonctif preserves an older Latin stem ('sapiam, sapias, sapiat...') that diverged from the regular present stem 'sav-' over centuries. The same kind of preservation explains être (sois), avoir (aie), aller (aille), faire (fasse), pouvoir (puisse). All six are high-frequency verbs whose subjonctif stems were used so often they resisted regularization.

'Que je sache' or '(autant) que je sache' = 'as far as I know' — a common hedge. 'Pierre est en vacances, que je sache' (Pierre is on vacation, as far as I know). The subjonctif 'sache' here is fossilized into an idiomatic phrase. Equivalent: 'à ma connaissance' (to my knowledge). One of the few subjonctif forms that appears in everyday speech without an explicit trigger.

The futur of savoir uses 'saur-': je saurai, tu sauras, il/elle/on saura, nous saurons, vous saurez, ils/elles sauront. The infinitive 'savoir' contracts to 'saur-' — same family as avoir → aur- and pouvoir → pourr-.

A handful of high-frequency French verbs developed contracted future stems for phonetic economy: avoir (aur-), savoir (saur-), pouvoir (pourr-), cabbat → cabr-, voir (verr-), devoir (devr-). Same pattern as Spanish saber → sabré. The 'v' of the infinitive drops to ease pronunciation.

Both express future knowing. 'Je saurai' (futur simple) feels slightly more formal or further in time. 'Je vais savoir' (futur proche) is more conversational. The futur simple also expresses conjecture: 'il saura sûrement' (he'll surely know — prediction).

The conditionnel of savoir is: je saurais, tu saurais, il/elle/on saurait, nous saurions, vous sauriez, ils/elles sauraient. Same stem 'saur-' as the futur, plus imperfect endings.

'Je ne saurais' is a formal/literary alternative to 'je ne sais pas' — meaning 'I wouldn't know' or 'I couldn't say'. 'Je ne saurais vous dire' = I wouldn't know how to tell you. The conditional makes it softer and more polite. Often used in writing or formal speech; in everyday conversation, 'je ne sais pas' is preferred.

Use it for: 1) Hypothetical knowing ('si j'étais là, je saurais' — if I were there, I'd know), 2) Polite phrases ('je ne saurais vous dire' — I couldn't tell you), 3) Reported future-in-past ('il a dit qu'il saurait' — he said he would know). The conditional softens or hedges any statement about knowledge.