In short

A conjunction (spójnik) is a joining word that links two clauses or two phrases. You already met the five everyday coordinators in Lesson 14; this lesson gathers the fuller B1 set and, more importantly, the subordinating conjunctions that build complex sentences - “that”, “because”, “so that”, “if”, “when”, “although”. The headline point for Polish is the żeby / aby / by family, which fuses personal endings onto itself and forces a special verb form. Get that pattern and the comma rules right, and your sentences jump from A2 to solid B1.

The rule

Polish conjunctions split into two families.

Coordinating conjunctions (spójniki współrzędne) link two clauses of equal rank - each could stand alone. They never change form. This is Lesson 14’s territory (i, a, ale, lub, więc), extended here with the more literary or precise members (oraz, lecz, albo, czy, natomiast, jednak, dlatego, zatem).

Subordinating conjunctions (spójniki podrzędne) attach a dependent clause to a main one; the subordinate clause cannot stand alone. In Polish a subordinate clause is almost always preceded by a comma - this is a rule, not a stylistic choice.

• Wiem, że masz rację. = I know that you are right.
• Zostaję w domu, bo pada. = I am staying home because it is raining.

że vs żeby - “that” is two words in Polish

This is the split that trips learners most.

• że = that, reporting a fact - after verbs of saying, thinking, knowing, feeling.
  • Myślę, że to jest dobry pomysł. = I think that this is a good idea.
• żeby (= aby, more formal) = so that / in order to / that, after verbs of wishing, wanting, asking, telling, ordering, or to express purpose.
  • Chcę, żeby on został. = I want him to stay. (literally “I want that he stay”)

Rule of thumb: if you could paraphrase the English with “in order to” or a wish/command (“I want… to”, “I told… to”), use żeby; if you are just reporting a fact, use że.

The żeby / aby / by family fuses personal endings

Like the conditional by (Lesson 37), żeby and aby carry the personal ending on themselves, and the verb in the clause appears in its -ł / -ła past-participle form (not the present):

• Chcę, żebyś przyszedł. = I want you to come. (żeby + -ś + przyszedł)
• Powiedziała mi, żebym poczekał. = She told me to wait. (żeby + -m + poczekał)

When the main clause and the subordinate clause share the same subject, drop the ending and use bare żeby + infinitive:

• Poszedłem do sklepu, żeby kupić chleb. = I went to the shop to buy bread.

When the subjects differ, you must use żeby + fused ending + past form (in the 3rd person the ending is zero, so żeby stays bare):

• Poszedłem do sklepu, żeby żona miała chleb. = I went to the shop so that my wife would have bread.

Causal conjunctions: bo, ponieważ, gdyż, dlatego że

All mean “because”, but they are not interchangeable in position:

• bo - everyday, spoken; it cannot begin a full sentence, only follow the main clause.
• ponieważ - neutral, can open the sentence: Ponieważ pada, zostaję. = Since it is raining, I am staying.
• gdyż - bookish equivalent of bo.
• dlatego że - “for the reason that”, emphatic.

Correlative (paired) conjunctions

Some conjunctions come in matched pairs framing both elements:

• i… i… = both… and…
• ani… ani… = neither… nor… (needs the verb negated: Nie mam ani czasu, ani pieniędzy.)
• albo… albo… = either… or… (exclusive)
• nie tylko… ale (też / także)… = not only… but (also)…
• zarówno… jak i… = both… as well as…
• im… tym… = the (more)… the (more)… (each half takes a comparative: Im szybciej, tym lepiej. = The faster, the better.)

Forms & patterns

Conjunctions are invariable - the only family that changes shape is żeby / aby / by, which glues on the personal ending. Learn that paradigm; everything else is a fixed word plus a comma rule.

żeby / aby / by - fused personal endings

The clause verb takes the past-participle form (the same -ł / -ła / -ło / -li / -ły stem as the past tense and the conditional), agreeing in gender and number with its subject:

Same-subject vs different-subject purpose clause:

Conjunctions by function

Correlative pairs

Examples

Common mistakes

• Chcę, że przyjdziesz. -> Chcę, żebyś przyszedł. - verbs of wanting/wishing take żeby + past form, never że + present.
• Myślę, żeby to jest dobre. -> Myślę, że to jest dobre. - reporting a plain fact needs że, not żeby.
• Idę do sklepu, żebym kupić chleb. -> Idę do sklepu, żeby kupić chleb. - same subject = bare żeby + infinitive, no personal ending.
• Powiedziałem, żeby ona przyjdzie. -> Powiedziałem, żeby przyszła. - after żeby the verb takes its past form, not the future; the pronoun can go, since the verb form already shows the subject.
• Wiem że masz rację. -> Wiem, że masz rację. - a subordinate clause always takes a comma before the conjunction.
• Bo pada, zostaję w domu. -> Ponieważ pada, zostaję w domu. - bo cannot open the sentence; use ponieważ.
• Nie mam ani czasu i pieniędzy. -> Nie mam ani czasu, ani pieniędzy. - the pair is ani… ani…, with the verb negated.
• Chcę żebyś przyszedłeś. -> Chcę, żebyś przyszedł. - the ending sits on żeby (żebyś); the verb stays the plain -ł form.

Tips

• Two-word test for “that”: can you rephrase as “in order to” or a wish/command? -> żeby. Just stating a fact? -> że.
• The ending rides on żeby, not the verb: żebym, żebyś, żebyśmy, żebyście. The verb is simply the -ł / -ła / -li form, exactly like the conditional (Lesson 37) minus the standalone by.
• Same subject -> żeby + infinitive; different subjects -> żeby + ending + past form. This one contrast fixes most purpose-clause errors.
• Every subordinate clause wants a comma in front of its conjunction - Polish is far stricter about this than English.
• Register pairs: że / bo / albo are everyday; iż / gdyż / lub are the bookish twins. Learn the plain one first. (choć and chociaż are not a register pair - both are everyday; choć is simply the shortened variant.)
• ani… ani… and single ani both demand a negated verb - Polish uses double negation (Lesson 25). The nie after dopóki is not that: the until reading requires it and it negates nothing - Czytam, dopóki nie zasnę. = I read until I fall asleep.