Learn Hardcore Ukrainian: З кожним уроком я почуваюся більш упевненим.

з = with (in the sense of as something happens / accompanying something).
кожним уроком = each lesson in the instrumental case (more on that in another question).

In this context, з + instrumental expresses a gradual change that happens together with each new lesson, similar to English “with every lesson, …” or “as each lesson passes, …”.

You would not use з + genitive here; з кожним уроком is the standard way to express this idea of gradual progress accompanying each lesson.

What case is кожним уроком, and why is that case used?

кожним уроком is in the instrumental case:

кожен урок (nominative, “each lesson”)
кожним уроком (instrumental, “with each lesson”)

The instrumental is used for several reasons in Ukrainian; one of them is after certain prepositions, including з when it means “with (together with), in the course of, as … happens”.

So:

з кожним уроком = with each lesson / as each lesson passes

The structure з + instrumental is very common for this idea of something changing or happening along with another process.

What does почуваюся mean exactly, and why does it have -ся at the end?

Почуваюся comes from the verb почуватися, which means “to feel (in terms of state or condition)”, as in to feel happy, tired, confident, better, worse, etc.

The ending -ся is a reflexive suffix. It often corresponds to “oneself” in English, but in many fixed expressions it just marks that the verb describes your state, feelings, or inner condition.

So:

я почуваюся ≈ “I feel” (in terms of how I am, what state I’m in)

Compare:

я почуваюся добре – I feel good / I’m feeling well
я почуваюся більш упевненим – I feel more confident

You could also see почувати себе, but почуватися with -ся is the most natural and common form for describing how you feel.

Why is it почуваюся, not почуваю?

Почуваю (without -ся) is rarely used on its own; to describe your state, Ukrainian normally uses the reflexive form почуватися.

я почуваюся щасливим – I feel happy
я почуваюся втомленим – I feel tired

If you said just я почуваю, it would sound incomplete or strange, because the verb strongly prefers either:

the reflexive form почуватися (to feel as a state), or
почувати with a direct object in some specialized uses (e.g., older or more formal style, or with nouns like почувати біль – “to feel pain”), but that’s much less common in everyday speech.

So in normal, modern usage for emotions or states, you almost always say почуваюся.

What form is упевненим, and why does it end in -им?

Упевненим is an adjective in the instrumental case, masculine singular.

Base form:

упевнений – confident (masculine, nominative)

Instrumental masculine singular of this adjective is:

упевненим – as/being confident

In Ukrainian, after verbs like бути (to be) and почуватися (to feel), the state or role is very often expressed in the instrumental case, not nominative:

Я є вчителем. – I am a teacher. (literally “I am by a teacher”)
Я почуваюся втомленим. – I feel tired.
Я почуваюся більш упевненим. – I feel more confident.

So упевненим is in the instrumental because it’s the predicative complement describing the state you feel yourself in.

Why is упевненим masculine if the subject is я (“I”)? What if the speaker is female?

Я doesn’t have grammatical gender by itself, so the gender is shown by the adjective that refers to я.

упевненим is masculine instrumental singular.
- This implies the speaker is male.
If the speaker is female, the adjective changes:
- Nominative feminine: упевнена
- Instrumental feminine: упевненою

So:

(man speaking):
З кожним уроком я почуваюся більш упевненим.
(woman speaking):
З кожним уроком я почуваюся більш упевненою.

Everything else in the sentence stays the same; only the adjective changes to match the speaker’s gender.

Why is it більш упевненим and not just упевненим?

Більш means “more”, so більш упевненим means “more confident”, not just “confident”.

я почуваюся упевненим – I feel confident
я почуваюся більш упевненим – I feel more confident (than before, gradually, etc.)

In your sentence, the idea is about progress over time (with each lesson), so більш (more) is needed to show increasing confidence, not just the existence of confidence.

Can we say упевненішим instead of більш упевненим? Is there a difference?

Yes, you can. Both are correct:

більш упевненим – more confident (analytic comparative with більш)
упевненішим – more confident (synthetic comparative with suffix -іш-, also in instrumental masculine singular)

So the whole phrase could be:

З кожним уроком я почуваюся більш упевненим.
З кожним уроком я почуваюся упевненішим.

Both sound natural. The version with -іш- (упевненішим) is very common and perhaps a bit more compact and “native-sounding,” but більш упевненим is absolutely fine and widely used.

Why is упевненим in the instrumental? Could I say я почуваюся більш упевнений in the nominative?

The instrumental after verbs like бути and почуватися is the normal, standard pattern in Ukrainian for describing a state or role:

Я був хворим. – I was ill.
Я почуваюся щасливим. – I feel happy.
Я почуваюся більш упевненим. – I feel more confident.

Saying я почуваюся більш упевнений (nominative) would sound unnatural or incorrect to most native speakers. The instrumental упевненим is what you should use here.

Can I change the word order, for example: Я з кожним уроком почуваюся більш упевненим?

Yes, Ukrainian word order is relatively flexible, and several variants are possible and natural:

З кожним уроком я почуваюся більш упевненим.
Я з кожним уроком почуваюся більш упевненим.
Я почуваюся більш упевненим з кожним уроком.

They all keep the same basic meaning. The differences are subtle and about emphasis:

Starting with З кожним уроком highlights the process of learning/lessons.
Starting with Я emphasizes yourself a bit more.
Putting з кожним уроком at the end can sound a bit more like an afterthought: “I feel more confident, with each lesson.”

All of them are grammatically correct.