Turistická trasa je dlouhá.

Because they both agree with trasa.

In Czech, adjectives must match the noun they describe in gender, number, and case.
Here, trasa is feminine singular nominative, so:

• turistický → turistická
• dlouhý → dlouhá

So the pattern is working exactly as Czech grammar requires.

A very common clue is the ending -a. Many Czech nouns ending in -a are feminine, and trasa is one of them.

You still have to learn noun gender as part of the vocabulary item, but the ending often helps. So it is useful to remember:

• trasa = feminine

That is why the adjectives around it also take feminine forms.

It is in the nominative singular.

That is because turistická trasa is the subject of the sentence: it is the thing being described as long.

Also, after je in this kind of sentence, Czech normally uses an adjective in the nominative as well:

• Turistická trasa je dlouhá.

So both the noun phrase and the predicate adjective are in forms appropriate for a nominative subject.

Je is the 3rd person singular present form of být = to be.

So:

• je = is

In normal standard Czech, you usually do not omit it in a sentence like this.
That is different from some other Slavic languages, where the present-tense to be may be left out.

So Turistická trasa dlouhá would not be the normal full sentence.

Because Czech uses an adjective, not an adverb, after být in this sentence.

You are describing the noun trasa, so you need the adjective dlouhý in the correct agreeing form:

• masculine: dlouhý
• feminine: dlouhá
• neuter: dlouhé

Since trasa is feminine, the correct form is dlouhá.

An adverb such as dlouze means something more like at length / in a lengthy way, so it would not fit here.

Czech has no articles.

So Czech does not normally have separate words matching English a/an and the. Whether something means a tourist trail, the tourist trail, or just tourist trail depends on context.

That is completely normal in Czech.

It usually means something like:

• tourist route
• hiking trail
• marked tourist trail

The exact English translation depends on context. In Czech, turistická trasa is a very common phrase for a route intended for walkers/hikers/tourists, often a marked path.

So even though turistická looks like touristic, the natural English translation is often hiking or tourist rather than touristic.

A simple learner-friendly pronunciation guide is:

TOO-ris-tits-kaa TRA-sa ye DLOU-haa

A few useful points:

• Czech stress is usually on the first syllable of each word.
• c is pronounced like ts.
• č is pronounced like ch in check.
• ou in dlouhá is a real diphthong, roughly like oh-oo said quickly.
• h in Czech is pronounced clearly.

So:

• Turistická ≈ TOO-ris-tits-kaa
• trasa ≈ TRA-sa
• je ≈ ye
• dlouhá ≈ DLOU-haa

Yes, Czech word order is more flexible than English, but the neutral order here is:

• Turistická trasa je dlouhá.

If you change the order, the meaning stays similar, but the focus or emphasis changes.

For example:

• Je turistická trasa dlouhá? = Is the tourist trail long?
• Dlouhá je turistická trasa. = marked/emphatic, not the most neutral way to say it

So for a basic statement, the original order is the safest and most natural.

It would be:

• Turistické trasy jsou dlouhé.

Changes:

• turistická → turistické
• trasa → trasy
• je → jsou
• dlouhá → dlouhé

So the sentence means The tourist trails are long or Tourist trails are long, depending on context.

No. Czech has several related words, and they are not always interchangeable.

For example:

• trasa = route, course, trail
• cesta = road, way, journey, path
• stezka = path, trail
• chodník = sidewalk/footpath

In the phrase turistická trasa, trasa is very natural and common. It suggests a route intended for tourists or hikers, often an established one.

So this sentence is not just grammatically correct; it also sounds natural.