Learn Hardcore Polish: To był mój błąd, ale spróbuję go naprawić. - That was my mistake, but I will try to fix it.

In the pattern to + być + noun in the past tense, the verb być agrees with the gender and number of the noun that follows. Błąd is masculine singular, so we use był.

Feminine: To była moja wina.
Neuter: To było nieporozumienie.
Plural (masc. personal): To byli moi rodzice.
Plural (non‑masc. personal): To były drobne błędy.

Why is it nominative mój błąd and not instrumental moim błędem?

With the structure to + być + noun, the noun is typically in the nominative: To był mój błąd. The instrumental is used in the pattern X jest Y‑instrumental (e.g., Jan jest lekarzem). You can say To było moim błędem, but it’s more formal and often used when followed by a clause: To było moim błędem, że tak zrobiłem.

Why is it mój and not moja or moje?

The possessive must agree with the noun’s gender and number. Błąd is masculine singular, so mój is required.

Feminine: moja (e.g., moja wina)
Neuter: moje (e.g., moje zadanie)
Masc. personal plural: moi (e.g., moi koledzy)

What does go refer to, and why that form?

Go is the unstressed object pronoun “him/it” for masculine singular. It refers back to błąd (masculine). It’s the accusative form of on used as an object: spróbuję go naprawić = “I’ll try to fix it.”
Note: jego/niego is used mainly after prepositions or for emphasis (e.g., bez niego), not here.

Could I use to instead of go (e.g., spróbuję to naprawić)? What’s the difference?

Yes.

spróbuję go naprawić ties the pronoun directly to a specific masculine noun just mentioned (błąd).
spróbuję to naprawić uses neutral to “this/it,” often pointing to the situation or the thing just referred to. Both are fine here.

Where should go go? Is spróbuję naprawić go also correct?

Default, most natural placement is right after the finite verb: spróbuję go naprawić.
Other options:

spróbuję naprawić go — acceptable, a bit more “end‑heavy.”
naprawić go spróbuję — possible but marked, used for emphasis or style. Avoid starting the clause with go in neutral speech.

Why is it spróbuję and not próbuję?

spróbuję is the simple future of the perfective verb spróbować (“I will try (once / make an attempt)”).
próbuję is present tense, imperfective (“I’m trying”).
For “I will be trying,” use the future of the imperfective: będę próbował (m) / będę próbowała (f).

Why naprawić and not naprawiać?

After spróbować, Polish normally takes a perfective infinitive to express a single, goal‑oriented attempt: spróbuję naprawić.
spróbuję naprawiać sounds odd; it suggests “I’ll try doing repair work (as an ongoing activity),” not a single fix.

Is naprawić błąd idiomatic, or should it be poprawić błąd?

Both exist, but they differ slightly:

poprawić błąd = correct the mistake itself (in a text, code, calculation).
naprawić błąd = remedy the effects/consequences of a mistake (fix what the mistake caused).
In many contexts people use them interchangeably, but this nuance often holds.

What’s the difference between błąd and wina?

błąd = a mistake, an error (you did something incorrectly).
wina = fault/blame/culpability (you are responsible).
So To był mój błąd is “That was my mistake.” To moja wina is stronger: “It’s my fault.”

Why is there a comma before ale?

In Polish, you put a comma before ale when it joins two clauses: To był mój błąd, ale spróbuję go naprawić. This is a standard punctuation rule.

How do I pronounce the tricky parts (ł, ą, ó, ę)?

ł = like English “w”: błąd ≈ “bwuond” (roughly).
ą before d sounds like nasal “on/own”: błąd ≈ “błond” (still nasal; not exactly “on”).
ó = like u: spróbuję ≈ “sprubuy-e.”
Final -ę is often pronounced like plain “e” in everyday speech: spróbuję ≈ “spróbuje.”
Stress is usually on the penultimate syllable: spró‑BÚ‑je.

Do I need to say Ja spróbuję…?

No. Polish usually omits subject pronouns because the verb ending shows the person. Spróbuję already means “I will try.” Use Ja only for emphasis or contrast: Ja spróbuję, a on nie.

Can I say it in the present: To mój błąd, ale spróbuję…?

Yes. To mój błąd = “It’s my mistake (now),” which fits when you’re acknowledging it in the moment. To był mój błąd points to something that already happened.

Can I also say Był to mój błąd?

Yes. Był to mój błąd is a stylistic inversion that sounds a bit more formal or rhetorical. Neutral, everyday speech prefers To był mój błąd.