Inversion after certain adverbs and in formal style (aussi, peut-être, à peine)

Peut-être viendra-t-il demain.Perhaps he'll come tomorrow.

You already know subject-verb inversion from forming formal questions — Viens-tu ? But that same inversion also shows up outside questions entirely, in formal written French, once certain adverbs open a clause: causal aussi ("therefore") and peut-être call for it fairly firmly, à peine requires it outright, and ainsi/du moins offer it as one literary option among others.

Quick shortcut: front one of these adverbs, and the subject pronoun can invert after the verb — exactly like a question, but the sentence is still a statement.

The adverbs involved

Placed at the very start of a clause, these adverbs can pull the subject after the verb:

• Peut-être ("perhaps"): Peut-être a-t-elle raison. (Perhaps she's right.)
• Sans doute ("probably"): Sans doute est-il déjà parti. (He's probably already left.)
• À peine ("hardly, scarcely"): À peine avait-il fini qu'on l'appelait déjà. (He'd hardly finished when he was already being called.)
• Ainsi ("thus, so"): Ainsi s'achève notre histoire. (Thus ends our story.)
• Du moins ("at least"): Du moins pouvons-nous l'espérer. (At least we can hope so.)

Ainsi and du moins are looser than the others: inversion after them is a literary stylistic choice, not a requirement — plain word order with a comma, Ainsi, elle a fini par accepter or Du moins, il faut essayer, is just as correct and, in everyday writing, more common. Peut-être leans more firmly toward needing some repair when fronted (see below), and à peine needs it outright.

Moved to any other position in the sentence, none of these adverbs force inversion — Elle a peut-être raison is completely normal, no inversion needed. It's specifically the fronted position that opens the door to it.

Aussi: two different words depending on position

Fronted, aussi means "therefore/so" and triggers inversion — a completely different word from the aussi you already know:

• ✅ Aussi a-t-il décidé de partir. (So he decided to leave.) — aussi = "therefore," fronted, inversion.
• ✅ Il a aussi décidé de partir. (He also decided to leave.) — aussi = "also," not fronted, no inversion.

Mixing these up changes the meaning of the sentence, not just its word order — always check which sense of aussi is meant before deciding whether inversion applies.

The everyday alternative: que + normal word order

Peut-être has a much more common, spoken-friendly alternative: keep it fronted, add que, and leave the word order completely normal:

• Peut-être qu'il viendra demain. (Perhaps he'll come tomorrow.) — same meaning as peut-être viendra-t-il demain, no inversion at all.

This que-version is the one you'll actually hear in conversation; the inverted version belongs to formal writing. Sans doute can appear with que too in casual speech, but its cleanest everyday option is simply not fronting it at all: Il est sans doute déjà parti — sitting in its ordinary mid-sentence position, no special construction needed. À peine has no que-alternative — inversion is its only option when fronted.

À peine... que: one thing right after another

À peine has its own fixed pattern for saying one thing happened immediately before another: à peine + inverted clause + que + the second event, often with the first clause in the plus-que-parfait and the second in the passé composé or présent:

• *À peine étions-nous sortis **qu'*il a commencé à pleuvoir. (We'd hardly gone outside when it started raining.)
• À peine le film avait-il commencé que tout le monde s'est tu. (The film had hardly begun when everyone fell silent.)

With a noun subject, as in the second example, the noun itself doesn't move — only a pronoun echo of it inverts after the verb, exactly like in formal question inversion with a noun subject.

Common mistakes

• ❌ Peut-être il viendra. → ✅ Peut-être viendra-t-il. / ✅ Peut-être qu'il viendra. (a fronted peut-être needs either inversion or que — not plain declarative word order)
• ❌ Aussi il a décidé de partir. (meaning "therefore") → ✅ Aussi a-t-il décidé de partir. (fronted aussi meaning "therefore" needs inversion)
• ❌ À peine il avait fini qu'on l'appelait. → ✅ À peine avait-il fini qu'on l'appelait. (à peine has no que-alternative — inversion is required when it's fronted)

Quick check

Key takeaways

• A handful of adverbs — causal aussi ("therefore"), peut-être, sans doute, à peine firmly, ainsi/du moins more loosely — open the door to subject-verb inversion when they start a clause; moved elsewhere, none of them do.
• Fronted aussi means "therefore" and calls for inversion — a different word from the everyday "also" aussi, which never triggers it.
• Peut-être has an everyday alternative: keep it fronted, add que, and use normal word order — the version you'll actually hear spoken. Sans doute's cleanest everyday option is simply not fronting it at all.
• À peine has no que-alternative; fronted, it always needs inversion, often as part of the fixed à peine... que pattern for one event following right after another. Ainsi/du moins can invert too, but plain comma-set-off word order is just as correct after them.