Wełna jest ciepła.

Because wełna is a feminine singular noun, and adjectives in Polish must agree with the noun in gender, number, and usually case.

• ciepły = masculine singular
• ciepła = feminine singular
• ciepłe = neuter singular

Since wełna is feminine, the adjective must also be feminine: ciepła.

Jest is the 3rd person singular present tense form of the verb być, meaning to be.

So:

• ja jestem = I am
• ty jesteś = you are
• on/ona/ono jest = he/she/it is

In Wełna jest ciepła, jest means is.

Normally, no. In standard Polish, if you are making a normal present-tense statement like Wool is warm, you usually keep jest.

So the natural sentence is:

• Wełna jest ciepła.

Polish sometimes omits forms of to be in special contexts, but not in a basic sentence like this one.

The ending -a very often suggests a noun is feminine in Polish, and wełna is feminine.

However, -a does not always mean feminine. There are some masculine nouns ending in -a, especially words for male people, for example:

• mężczyzna = man
• kolega = male friend/colleague

So -a is a strong clue, but not an absolute rule.

A rough English approximation is VEW-na, with the stress on the first syllable:

• weł sounds roughly like vew
• na sounds like nah

Important pronunciation point:

• ł in modern Polish sounds like English w

So wełna is not pronounced with an English l sound.

A rough approximation is CHYEH-pwa, with stress on the first syllable.

A few details:

• cie sounds somewhat like chye
• pł includes ł, which sounds like w
• final a is like ah

So the ł again sounds like w, making pła sound roughly like pwa.

Yes, you can say Ciepła wełna, but it means something slightly different in structure.

• Wełna jest ciepła. = The wool is warm.
  This is a full sentence: noun + is

  • adjective.

• Ciepła wełna = warm wool
  This is a noun phrase, not a full sentence.

So:

• ciepła wełna describes the noun
• wełna jest ciepła makes a statement about it

It is in the nominative singular.

That is the basic dictionary form of the noun, and it is used here because wełna is the subject of the sentence.

Similarly, ciepła is also in the nominative singular feminine form, agreeing with wełna.

In this sentence, ciepła is definitely an adjective meaning warm.

But in Polish, forms like ciepła can sometimes belong to different grammatical patterns depending on context. For a beginner, the important point here is:

• ciepły / ciepła / ciepłe are adjective forms
• here ciepła matches the feminine noun wełna

So in this sentence, treat it simply as the feminine form of ciepły.

Polish does not have articles like English a or the.

So wełna can mean:

• wool
• the wool

Which one is intended depends on context.

That is very normal in Polish, and learners need to get used to understanding definiteness from the situation rather than from a separate word.

Yes. Polish word order is more flexible than English, though the most neutral version here is:

• Wełna jest ciepła.

You could also hear:

• Ciepła jest wełna.
• Jest ciepła wełna. — but this is less neutral and more context-dependent

Changing the order usually changes emphasis, not the basic meaning.

For learners, the safest standard order is:

• subject + jest + adjective

Polish stress is usually on the second-to-last syllable, not always the first.

In these two words:

• wełna has 2 syllables, so stress falls on the first: WEŁ-na
• ciepła also has 2 syllables, so stress falls on the first: CIE-pła

So they sound first-syllable-stressed only because they are two-syllable words. The general rule is still penultimate stress.

No. They are related, but not the same.

• ciepła = warm
• gorąca = hot

So Wełna jest ciepła means the wool is warm, not hot.

That distinction is the same as in English:

• a warm sweater
• a hot stove

Yes. Polish adjectives must agree with the noun.

For example, with ciepły:

• koc jest ciepły = the blanket is warm
  masculine

• wełna jest ciepła = the wool is warm
  feminine

• mleko jest ciepłe = the milk is warm
  neuter

This agreement system is one of the most important parts of Polish grammar.