Learn Hardcore Ukrainian: Уночі вулиця тиха, і мені трохи страшно. - At night the street is quiet, and I feel a bit scared.

Grammatically it comes from the preposition у + the locative form ночі, but in modern language it behaves like a fixed adverb (you don’t change its form).

уночі and вночі mean the same thing: at night.
The choice between у and в is mostly about euphony (what sounds smoother in context). Both are standard.

You will see both:

Вночі було дуже холодно. – It was very cold at night.
Уночі вулиця тиха. – At night, the street is quiet.

In everyday speech, вночі is probably a bit more common, but уночі does not sound wrong or overly formal.

Why does Ukrainian say вулиця тиха without a word for is?

In Ukrainian, the verb бути (to be) is usually dropped in the present tense in simple sentences like this.

So:

English: The street is quiet.
Ukrainian literally: Street quiet. → Вулиця тиха.

You can think of an “invisible” є (is) between them:

Вулиця (є) тиха.

The verb бути appears in:

the past: Вулиця була тиха. – The street was quiet.
the future: Вулиця буде тиха. – The street will be quiet.
some emphatic/existential sentences: Тут є магазин. – There is a shop here.

But in neutral present descriptions, it’s simply omitted.

Why is it тиха, not тихий or тихо?

Тиха is an adjective that agrees with вулиця in gender and number.

The adjective тихий (quiet) has these main forms:

тихий – masculine singular
тиха – feminine singular
тихе – neuter singular
тихі – plural

Since вулиця (street) is feminine singular, we need тиха:

тихий парк – a quiet park (masc.)
тиха вулиця – a quiet street (fem.)
тихе місто – a quiet city (neut.)
тихі вулиці – quiet streets (plural)

Тихо is an adverb and/or a predicative word meaning quietly / it is quiet. You’d use it when there is no specific noun being described:

На вулиці тихо. – It is quiet in the street.

In your sentence we are describing the street, so we use the adjective тиха, not the adverb тихо.

What case is вулиця, and why is that form used here?

Вулиця is in the nominative singular.

The nominative case is used for the subject of the sentence – the thing that “does” or “is” something.
Here, вулиця is the subject: it is the thing that (is) quiet.

Basic dictionary form: вулиця (street) – nominative singular.
Other forms (for comparison):

genitive: вулиці – of the street
locative: на вулиці – on the street

In Уночі вулиця тиха, we need the subject form, so we use nominative: вулиця.

Why is it мені трохи страшно and not я трохи страшний / страшна?

In Ukrainian, feelings like I’m scared, I’m cold, I’m sad are very often expressed with:

dative pronoun (to me) + a special word like страшно, холодно, сумно etc.

So:

Мені страшно. – I’m scared. (literally: To me (it is) scary.)
Мені трохи страшно. – I’m a bit scared.

If you say:

Я страшний (masc.) / Я страшна (fem.),
that usually means I am scary / I look frightening / I’m ugly, i.e. I am a frightening person or look – not “I feel afraid.”

So:

Use мені страшно / мені трохи страшно for I feel scared / a little scared.
Avoid я страшний / я страшна unless you really mean I am scary / ugly.

What exactly is страшно here – an adjective or an adverb? How is it used?

Words like страшно, холодно, сумно, весело, шкода, жаль form a special group often called “predicative adverbs” or “words of state”.

Key points:

They typically end in -о.
They don’t change for gender, number, or case.
They are used in the predicate, often with a dative pronoun.

Examples:

Мені страшно. – I’m scared.
Тобі холодно. – You’re cold.
Йому сумно. – He is sad.
Нам весело. – We are having fun.

In мені трохи страшно, страшно is this kind of predicative word: it describes the state/feeling of the (dative) person, not a permanent quality of a noun.

Why is мені in the dative case, and how does this construction work with other feelings?

Мені is the dative form of я (I) and literally means to me.

In Ukrainian, many feelings and physical states are expressed as:

Dative pronoun (to someone) + predicative word (cold, scary, sad, etc.)

This structure answers the question кому? – to whom? (dative).

Dative pronouns:

мені – to me
тобі – to you (sing.)
йому / їй – to him / to her
нам – to us
вам – to you (pl./formal)
їм – to them

Common patterns:

Мені холодно. – I’m cold.
Тобі жарко. – You’re hot.
Йому нудно. – He is bored.
Їй весело. – She is having fun.
Нам сумно. – We are sad.
Вам шкода? – Do you feel sorry?
Їм страшно. – They are scared.

So мені трохи страшно literally is To me (it is) a little scary, which is how Ukrainian usually says I’m a little scared.

What does трохи add to the sentence? Can it be changed or moved?

Трохи means a little, a bit, slightly, somewhat.

Мені страшно. – I am scared. (neutral / can be quite strong)
Мені трохи страшно. – I’m a little bit scared / I’m somewhat scared.

So трохи softens the intensity of the feeling.

Possible variants:

Мені трохи страшно. – standard, natural.
Мені дуже страшно. – I’m very scared.
Мені зовсім не страшно. – I’m not scared at all.

Word order:

Мені трохи страшно is normal.
Мені страшно трохи sounds awkward in most contexts.
Трохи мені страшно is possible but more marked, with emphasis on a bit.

Colloquial synonym: трошки – Мені трошки страшно. – I’m a little bit scared.

Why is there a comma before і in ... тиха, і мені трохи страшно?

Because і here links two independent clauses:

Уночі вулиця тиха – At night the street is quiet.
(Уночі) мені трохи страшно – (At night) I feel a bit scared.

Each part has its own subject and predicate (even though the verb є is omitted), so in Ukrainian spelling rules a comma is required before і:

Уночі вулиця тиха, і мені трохи страшно.

If і connects just two words or short phrases (not full clauses), then you do not put a comma:

Тиха і темна вулиця. – A quiet and dark street. (no comma)

Here, though, they are full sentences, so the comma is correct and necessary.

Is the word order fixed, or can we rearrange the parts of this sentence?

Ukrainian word order is relatively flexible, but not all permutations sound equally natural.

Your version:

Уночі вулиця тиха, і мені трохи страшно. – neutral and natural.

Other possible but slightly different versions:

Вулиця уночі тиха, і мені трохи страшно.
– Emphasis that it is quiet at night (maybe not during the day).
Уночі тиха вулиця, і мені трохи страшно.
– More poetic, with a bit of focus on тиха вулиця as a whole phrase.

The second clause:

Мені трохи страшно is the normal order.
Трохи мені страшно – possible, with emphasis on трохи.
І трохи страшно мені – sounds odd or at least very marked; pronouns like мені usually appear earlier in the clause.

So you can move уночі and sometimes shift трохи for nuance, but the given order is the most straightforward conversational one.

How do you pronounce this sentence? Where is the stress in each word?

Stresses (´ marks the stressed vowel):

уночі́ – u‑no‑CHÍ
ву́лиця – VÚ‑ly‑tsia
ти́ха – TÝ‑kha
і – i (no stress issue; it’s a single syllable)
мені́ – me‑NÍ
тро́хи – TRÓ‑khy
стра́шно – STRÁ‑shno

Full sentence with stressed syllables indicated:

уночі́ ву́лиця ти́ха, і мені́ тро́хи стра́шно.

Pronunciation tips for English speakers:

ч = like ch in church.
х = a hard kh sound (like German Bach), not like English h.
ц = ts (as in cats).
ш = sh in shoe.

All vowels are short and clear, not reduced like in English unstressed syllables.