Ten fotel jest twardszy niż tamten, ale jest wygodny.

Ten means this and must agree with fotel in gender, number, and case.

• fotel is masculine singular nominative
• so the correct form is ten fotel = this armchair

Compare:

• ten fotel — this armchair
• ta sofa — this sofa
• to krzesło — this chair

So to fotel would be wrong here, because to is the neuter form.

In Polish, many nouns ending in a consonant are masculine, and fotel ends in -l.

So:

• fotel → masculine
• therefore: ten fotel
• and predicate adjectives also use masculine singular forms: jest wygodny, jest twardszy

This is one reason Polish learners pay attention to noun endings early on: they often help predict gender.

Twardszy is the comparative form of twardy (hard / firm).

So:

• twardy — hard, firm
• twardszy — harder, firmer

Polish often forms comparatives by changing the adjective ending rather than using a separate word like more.

Examples:

• mały → mniejszy — small → smaller
• szybki → szybszy — fast → faster
• twardy → twardszy — hard/firm → harder/firmer

So jest twardszy means is harder / is firmer.

Because for many common adjectives, Polish prefers a synthetic comparative like twardszy instead of bardziej + adjective.

So:

• natural: twardszy
• less natural here: bardziej twardy

Bardziej is often used when:

1. a normal comparative is awkward or uncommon
2. the speaker wants a slightly different style
3. the adjective is harder to compare in the simple form

With twardy, twardszy is the standard choice.

Niż means than in comparisons.

So:

• twardszy niż tamten = harder than that one

It is the normal word used after comparatives.

Examples:

• wyższy niż ja — taller than me
• lepszy niż ten — better than this one
• droższy niż wcześniej — more expensive than before

Yes. Both are possible, but the grammar changes a little.

You can say:

• twardszy niż tamten
• twardszy od tamtego

The difference is:

• after niż, you often keep the same basic form: tamten
• after od, you use the genitive: tamtego

So both mean harder than that one.

In your sentence, niż tamten is completely natural.

Because the sentence uses niż, not od.

With niż, Polish commonly uses:

• ten
• tamten
• ja
• on, etc.

So:

• twardszy niż tamten — harder than that one

But with od, you need the genitive:

• twardszy od tamtego

That is why tamten is correct in the original sentence.

Tamten means that one here. The noun fotel is omitted because it is understood from context.

So the full idea is:

• Ten fotel jest twardszy niż tamten fotel

But Polish, like English, often leaves out repeated nouns when they are obvious:

• This armchair is harder than that one

So tamten is standing in for tamten fotel.

Because Polish often omits subject pronouns when the subject is clear from context.

In English, you must say:

• but it is comfortable

In Polish, the verb form and context usually make the subject clear, so you can simply say:

• ale jest wygodny

The understood subject is still ten fotel.

You could say ale on jest wygodny, but that would usually add emphasis, and in this sentence it is not necessary.

Because it describes the noun fotel.

• wygodny = comfortable (adjective)
• wygodnie = comfortably (adverb)

Here the sentence means:

• The armchair is comfortable

So you need the adjective that agrees with the noun:

• fotel jest wygodny

But if you were describing how someone sits, you would use the adverb:

• Siedzi wygodnie — He/She is sitting comfortably.

Because the sentence has two coordinated parts:

• Ten fotel jest twardszy niż tamten
• ale jest wygodny

Repeating jest makes the second statement complete and clear.

English does the same:

• This armchair is harder than that one, but it is comfortable.

In some contexts Polish can omit repeated elements, but here ale jest wygodny is the natural full structure.

Because ale means but, and in Polish a comma before ale is normally required.

So:

• Ten fotel jest twardszy niż tamten, ale jest wygodny.

This is standard Polish punctuation.

The same happens with other conjunctions in many cases, but ale is one of the clearest examples where learners should expect a comma.

It can mean either, depending on context.

With furniture like fotel, English often prefers firmer rather than harder, because that sounds more natural. But the Polish adjective twardy itself basically refers to something not soft.

So in context:

• Ten fotel jest twardszy niż tamten
  can mean
• This armchair is firmer than that one

That is often the most natural translation in English for seating.

Not completely. Polish word order is more flexible than English, but the original sentence is natural and neutral:

• Ten fotel jest twardszy niż tamten, ale jest wygodny.

You can move things around for emphasis, but not every version sounds equally natural.

For example, a variation like:

• Ten fotel jest wygodny, ale twardszy niż tamten

changes the emphasis: now comfortable is mentioned first, and the contrast feels slightly different.

So the original order is a good standard version for learners.

This word can feel difficult because of the consonant cluster.

A rough breakdown is:

• twar-dszy

Very roughly for an English speaker, it sounds like:

• TVAR-dshih
  with a rolled or tapped Polish r, and sz sounding like sh

A few helpful points:

• tw is pronounced together at the start
• ar is short and clear
• sz sounds like English sh
• the stress is on the second-to-last syllable, so: TWARD-szy

Polish spelling is quite regular, so once you learn common sound patterns, words like this become easier.