Learn Hardcore Czech: Můj kabát je starý, ale je teplý.

kabát is a masculine noun (masculine inanimate).
The masculine singular form of “my” is můj.
moje is the basic form for feminine nouns (and also for neuter plural).

So you say:

můj kabát – my coat (masculine)
moje kniha – my book (feminine)
moje auto – my car (neuter)

Why do the adjectives starý and teplý end in -ý?

The adjectives starý (old) and teplý (warm) must agree with kabát in gender, number, and case.

kabát = masculine singular, nominative case
The normal masculine singular nominative ending for adjectives is -ý.

So you get:

starý kabát – an old coat
kabát je starý – the coat is old
kabát je teplý – the coat is warm

For a feminine noun (e.g. kniha), you would use -á:

stará kniha, kniha je stará

What case is kabát in here?

Kabát is in the nominative singular.

It is the subject of the sentence: Můj kabát (My coat)
Predicate adjectives that describe the subject (starý, teplý) also appear in the nominative and agree with it.

So the structure is:

Subject (nominative): Můj kabát
Verb: je
Predicate adjectives (nominative, agreeing with subject): starý, teplý

Why is je repeated: je starý, ale je teplý? Can we drop the second je?

You can drop the second je, and it will still be correct:

Můj kabát je starý, ale teplý.

Czech often omits repeated verbs in the second part of a coordinated structure when the meaning is obvious. Both versions are fine:

With je repeated: a bit more explicit, slightly more careful or “spelled out”.
Without the second je: more compact, very natural in everyday speech and writing.

Could I say Můj kabát je starý, ale on je teplý?

You could, but it would sound unusual in a normal context.

In Czech, subject pronouns (on, ona, ono) are usually omitted unless:

you need to emphasize who is doing something, or
you are contrasting subjects.

Here, the subject is the same (můj kabát), so on is unnecessary and sounds a bit awkward or over‑specified. The natural options are:

Můj kabát je starý, ale (je) teplý.

Why is there a comma before ale?

In Czech, you normally put a comma before the conjunction ale when it joins two clauses or parts of a sentence that are contrasted.

Můj kabát je starý, ale je teplý.

Here, you’re contrasting starý vs. teplý, so a comma is required.
This is similar to English: “My coat is old, but it is warm.”

Can I replace ale with a? What would change?

You can say:

Můj kabát je starý a teplý.

But a means and, so it simply adds qualities without contrast.

a: “My coat is old and warm.” (both are just facts)
ale: “My coat is old, but it is warm.” (old is slightly negative, warm is positive; they contrast)

So ale introduces a contradiction or unexpected combination, just like English but.

Could I say Kabát je můj instead of Můj kabát?

Yes, but it has a different focus and structure:

Můj kabát je starý, ale je teplý.
- “My coat is old, but (it is) warm.”
- You’re talking about the coat that belongs to you and describing it.
Ten kabát je můj.
- “That coat is mine.”
- Here můj works as a pronoun (“mine”), and the sentence focuses on who owns the coat, not its qualities.

So můj kabát = “my coat” (possessive adjective before the noun),
while kabát je můj = “the coat is mine” (predicative possessive).

Why doesn’t Czech use a word for “the” or “a” in můj kabát?

Czech does not have articles like English a/an or the.

kabát could mean “a coat” or “the coat”, depending on context.
můj kabát could be understood as “my coat”, “my jacket”, etc., but there is no separate word that marks definiteness.

The specificity (“this coat”, “that coat”, “a coat”) is usually clear from context or can be made explicit with words like:

ten kabát – that/the coat
nějaký kabát – some coat / a coat

How would the sentence change in the plural: “My coats are old, but they are warm.”?

You have to change the possessive, the noun, the verb, and the adjectives to plural:

Moje kabáty jsou staré, ale jsou teplé.

Breakdown:

můj → moje (masculine plural form of “my”)
kabát → kabáty (plural of “coat”)
je → jsou (3rd person singular → plural of “to be”)
starý → staré, teplý → teplé (adjectives agree with masculine animate/inanimate plural here)

How do you pronounce můj and what sound does ů in můj compare to?

Můj is pronounced roughly like [mooy] in English.

The letter ů represents a long “oo” sound:

ů ≈ a long u in “food”, held a bit longer.
So můj = m-ů-j, like “mooy”.

Note: ú and ů are pronounced the same; they just differ in where they appear in the word and some etymology, not in sound.

Why do starý and teplý come after the verb instead of before the noun (as in starý kabát)?

Czech has two common ways to use adjectives:

Attributive, before the noun:
- starý kabát – an old coat
- teplý kabát – a warm coat
Predicative, after the verb “to be”:
- Kabát je starý. – The coat is old.
- Kabát je teplý. – The coat is warm.

In your sentence, you are making full statements about the coat’s qualities, so the adjectives are predicative and come after je:

Můj kabát je starý, ale (je) teplý.

Is there any difference in meaning if I change the word order, like Kabát můj je starý, ale teplý?

Word order in Czech is flexible, but not all orders sound equally natural.

Můj kabát je starý, ale (je) teplý. – neutral, natural.
Kabát můj je starý, ale teplý. – grammatically possible, but sounds poetic or emphatic, not normal everyday speech.

By moving můj after kabát, you put special emphasis on můj (“the coat of mine”), as in poetry or contrastive speech. In normal conversation, keep můj before kabát.

Is there any register or style nuance in můj kabát je starý, ale je teplý? Is it formal, informal, or neutral?

The sentence is completely neutral in style.

The vocabulary (kabát, starý, teplý, ale) is standard.
The grammar is straightforward, with normal word order and no slang.

You can use it in everyday conversation, in writing, and in most contexts without sounding too formal or too casual.