Learn Hardcore Ukrainian: Петро майже спізнився, бо повернув не туди. - Petro almost was late because he turned the wrong way.

майже means “almost.” So Петро майже спізнився = “Petro was almost late.”
You can also say Петро ледь не спізнився. This is very idiomatic for a near miss.
Be careful with майже не спізнився. That means “he was almost not late” (i.e., he barely avoided being late or was late by a hair), which is a different nuance.

Why is there a comma before бо?

Because бо is a conjunction meaning “because” that introduces a clause of cause. Ukrainian normally places a comma before causal conjunctions like бо, тому що, оскільки. Hence: ..., бо ...

Can I use тому що or оскільки instead of бо? Any difference?

Yes:

бо = because (short, common, neutral‑informal).
тому що = because (neutral, very common).
оскільки = since/as (a bit more formal or explanatory). All three fit here: Петро майже спізнився, тому що/оскільки повернув не туди.

Why is there no pronoun він in the second clause?

Ukrainian often drops subject pronouns when the subject is clear from context. In the past tense, the verb shows gender/number, so повернув already tells you it’s masculine singular (i.e., “he”). You could add він for emphasis or clarity, but it’s not needed: ..., бо (він) повернув не туди.

What’s the difference between спізнився and запізнився?

They’re near‑synonyms meaning “was late.”

спізнитися and запізнитися are both standard; usage can be regional or stylistic.
With nouns, both спізнення and запізнення (“delay”) exist; you’ll often see запізнення in official contexts (e.g., “рейс із запізненням”).

What does the ending -ся in спізнився do?

It’s the reflexive/postfix pronoun used to form intransitive or reflexive verbs. спізнитися literally “to be late (oneself),” with no direct object. In rapid speech, you may hear the shortened -сь (e.g., спізнивсь).

What are the aspect and tense of спізнився and повернув?

Both are past tense, perfective, masculine singular:

спізнився = “(he) ended up being late” (completed event).
повернув = “(he) turned (once).” If you want the ongoing process, use imperfective: Петро спізнювався, бо повернув не туди = “Petro was running late because he turned the wrong way.”

Why is it повернув and not повернувся?

повернути = to turn (a vehicle/body) in some direction.
повернутися = to return/come back, or to turn oneself around. Here he made a wrong turn, so повернув is correct. повернувся не туди would mean “returned to the wrong place,” which is a different idea.

What does не туди literally mean, and how is it different from не там?

не туди = “not to there” → “the wrong way/direction” (directional; used with motion/turning).
не там = “not there” (location; wrong place). Related:
не сюди = “not this way (toward here).”
не в той бік / не в тому напрямку = “in the wrong direction.”
не на ту вулицю = “onto the wrong street.”

Can I say не туди повернув instead of повернув не туди?

Yes. Ukrainian word order is flexible. повернув не туди is neutral; не туди повернув puts extra emphasis on the wrong direction.

How do I say “turned left/right” naturally?

повернути ліворуч / праворуч
Also common: повернути наліво / направо Examples: Він повернув праворуч. / Він повернув наліво.

Is бо acceptable in formal writing?

Yes, it’s standard. In very formal or academic prose, writers often prefer оскільки or через те, що, but бо and тому що are both fine in most contexts.

Where is the stress in key words?

Петро́
ма́йже
спізни́вся
поверну́в
туди́
бо (single syllable)

Could I front the cause and say: Бо повернув не туди, Петро майже спізнився?

That sounds awkward. Бо rarely starts a sentence in neutral prose. If you want the cause first, use оскільки: Оскільки він повернув не туди, Петро майже спізнився. Otherwise, keep the original order.

What preposition goes with “be late for [something]” in Ukrainian?

Use на:

спізнитися/запізнитися на поїзд/урок/зустріч = “be late for the train/class/meeting.”

Is there a difference between повернути and звернути?

Both can mean “to turn,” but:

повернути is general: повернути ліворуч/праворуч.
звернути often implies turning off a route or onto something: звернути на вулицю Шевченка / з траси. In many contexts they’re interchangeable; choose by collocation.