Subordinating Conjunctions

A subordinating conjunction glues a dependent clause onto a main clause — I know *that you're right, we stayed **because it was raining. Czech has a rich set of these, and they share two iron rules that English does not: *a comma always sits in front of the conjunction, and a couple of them — aby and kdyby — actually fuse personal endings onto themselves. Get those two facts straight and the whole system opens up.

Rule 1: the comma is obligatory

Czech punctuation is grammatical, not stylistic. A subordinate clause is always fenced off by a comma — there is no "optional comma" the way English treats it. The comma goes immediately before the subordinating conjunction.

English would happily write "I think you're right" with no comma at all. In Czech the comma is mandatory — leaving it out is a spelling-level error, like dropping a letter. See subordinate clauses and commas for the punctuation in full.

Rule 2: no German-style verb-final order

If you have studied German, unlearn the verb-to-the-end reflex. Czech subordinate clauses keep the same flexible word order as main clauses; the verb does not get banished to the end. What does happen is that the clitics — the short auxiliary and pronoun words like jsem, se, si, mu, to — line up right after the conjunction, in the clause's second position.

In že se mu to nelíbí, the clitics se mu to cluster immediately after že, and the verb nelíbí sits in its natural place — not pushed to the end. This clitic-after-conjunction behaviour is the one piece of word order you do need to watch.

A semantic map of the main conjunctions

The everyday subordinators fall into five meaning groups. Learn them by what they do and the comma rule does the rest.

že — that

The basic complementiser. It introduces the content of what is thought, said, or known. Unlike English "that," it can never be dropped.

protože / jelikož — because, since

Protože is the neutral everyday "because"; jelikož is more formal and tends to open a sentence. More on cause in causal conjunctions.

když / až — when

Když covers "when" for the present and past (and "if" in real conditions); až is the "when" you use for the future — the moment something will happen. More in temporal conjunctions.

jestli / pokud — if (real condition)

Both mean "if" for conditions you treat as genuinely possible. Pokud also carries "as long as / provided that."

zatímco — while

Marks two things going on at the same time, often with a hint of contrast.

přestože / ačkoli — although

Concession: it admits something that runs against the main clause.

The special pair: aby and kdyby carry person endings

Here is the feature that catches every learner. Aby (so that, in order to) and kdyby (if — for unreal, hypothetical conditions) are not fixed words. They absorb the conditional auxiliary, so they change form by person:

Both are also followed by the past-tense (l-)participle of the verb, because they build on the conditional mood.

In the first sentence the purpose is "I" making it, so the conjunction is abych, paired with the l-participle stihl. In the second, the condition concerns "you," so it is kdybys, with měl. You cannot say aby jsem or kdyby jsi — the auxiliary is already baked into the conjunction. Dig deeper in the aby clause and kdyby conditional clauses.

Clause order is flexible

The subordinate clause can come first or second. When it comes first, a comma still separates the two clauses — it just falls at the join instead of mid-sentence.

The meaning is identical to Zůstali jsme doma, protože pršelo; fronting the cause clause simply foregrounds it.

Common Mistakes

Key Takeaways

• A comma always precedes a subordinating conjunction — no exceptions, in either clause order.
• There is no verb-final rule; only the clitics (jsem, se, si, mu, to) cluster right after the conjunction.
• aby and kdyby fuse the conditional auxiliary, changing by person (abych/abys/abychom/abyste, kdybych/kdybys…) and taking the l-participle.
• Sort the conjunctions by meaning: statement (že), cause (protože), time (když/až), condition (jestli/pokud/kdyby), purpose (aby), concession (přestože/ačkoli).