než

The conjunction než is highly frequent in standard Czech and performs three distinct roles.

1. Comparative než ("than")
When used with comparative adjectives or comparative adverbs, než introduces the standard of comparison. Crucially, než is a conjunction, not a preposition. It does not govern a specific case of its own. Instead, it requires case matching (parallelism). The word following než takes the exact same case as the word it is being compared to in the main clause.

• Comparing subjects (Nominative): Petr je vyšší než já. (Petr is taller than I [am].)
• Comparing objects (Accusative): Mám radši kávu než čaj. (I prefer coffee to tea.)

When comparing actions or expressing a preference, the structure depends on the main clause. If the main clause uses an infinitive, you can simply use an infinitive after než (e.g., Je lepší mlčet než mluvit.). If the main clause has a conjugated verb, než can be followed by a standard conjugated verb in the indicative mood (e.g., Raději čtu, než píšu.). However, to express a rejected, hypothetical, or unrealized action ("rather than doing X"), use než aby (note that aby must be conjugated for person and number: abych, abys, aby, abychom, abyste) followed by the past participle (l-participle) of the verb (e.g., Radši zůstanu doma, než abych tam šel.). This conjugated než aby construction is also used with příliš (too) to express "too [adjective] to [verb]" (e.g., Je příliš unavený, než aby pracoval. - He is too tired to work).

Note: In casual spoken Common Czech, you will often hear people use jak instead of než (e.g., větší jak já). However, standard written Czech strictly requires než. Additionally, in historical Czech, než was sometimes omitted, and the standard of comparison was placed in the bare genitive case (e.g., starší bratra). This construction is obsolete in everyday speech but can still be encountered in older literature, poetry, and highly elevated formal prose.

2. Temporal než ("before" / "until")
As a temporal conjunction, než introduces a subordinate clause describing an event that happens later than the main clause. It requires a conjugated verb. Because it usually sets a bounded deadline ("before X happens"), the verb is typically perfective (using the perfective present tense for future events). However, if the future event is a state or an ongoing process, you can and should use the compound future tense with budu (e.g., Chci to dokončit, než budu obědvat.).

For emphasis, temporal než is frequently preceded by dřív(e) or předtím (e.g., Skončíme dřív, než začne pršet.).

Important Nuances:

• "Until" (než vs. dokud ne): When the main clause involves waiting or a continuous state, než frequently translates to "until" in English (e.g., Počkej, než přijdu. - Wait until I arrive). However, it is important to distinguish než from dokud ne. While než focuses on the point in time before an event happens, dokud ne emphasizes the duration of the state leading up to that point (e.g., Nebudu jíst, dokud nepřijdeš. - I won't eat until you arrive).
• Preempted events: Temporal než can also take the conditional mood (než by) to express an unrealized or preempted event ("before [something] could happen", e.g., Zmizel dřív, než by ho někdo poznal.).

Important: English uses "before" for both clauses and nouns. In Czech, temporal než is a conjunction and requires a conjugated verb. To say "before a noun" (e.g., before the meeting), you must use the preposition před + instrumental case (e.g., před schůzkou). Do not confuse temporal než with až (future "when").

3. Exception ("except" / "but")
When paired with negative words like nic (nothing) or nikdo (nobody), or with the word jiný (other), než translates to "except" or "but". For example: Nemám nic než tebe. (I have nothing but you.)

Comma Rules (Interpunkce):
In Czech, no comma is used when než connects simple phrases without a verb (e.g., Petr je vyšší než já.). However, a comma is strictly required when než introduces a subordinate clause with its own conjugated verb (e.g., Skončíme dřív, než začne pršet.).