Західна дорога довга.

In Ukrainian, the present-tense form of to be is usually omitted in simple statements.

So:

Західна дорога довга
literally looks like
Western road long

but it naturally means:

The western road is long

If you added є, you could say Західна дорога є довга, but that is usually less neutral and often sounds unnecessary in a basic sentence.

Because they are both adjectives agreeing with дорога, which is a feminine singular noun.

In Ukrainian, adjectives change their endings to match the noun in gender, number, and case.

Here:

• дорога = feminine singular
• західна = feminine singular form of західний = western
• довга = feminine singular form of довгий = long

English adjectives do not change like this, but Ukrainian adjectives do.

They are in the nominative singular feminine.

• дорога is the subject, so nominative makes sense.
• західна agrees with дорога, so it is also nominative singular feminine.
• довга is a predicate adjective describing the subject, and in this kind of present-tense sentence it is also nominative.

So the whole structure is very regular and basic.

Because the two adjectives are doing different jobs.

• західна is an attributive adjective: it is part of the noun phrase західна дорога = western road
• довга is a predicate adjective: it tells you something about the road = is long

So the structure is:

[західна дорога] [довга]
[western road] [is long]

This is very similar to English:

• the western road
• the road is long

Yes, but that would usually mean something different.

Довга західна дорога is normally just a noun phrase:

a long western road
or
the long western road

It is not the same as the full statement The western road is long.

So:

• Західна дорога довга = full sentence
• Довга західна дорога = noun phrase

That difference is important.

It could mean either, depending on context.

Ukrainian has no articles like a or the, so definiteness is usually understood from the situation.

So західна дорога can mean:

• the western road
• a western road

In many teaching translations, English uses the because it sounds more natural in a sentence like this, but Ukrainian itself does not mark that directly.

Not here. It is capitalized simply because it is the first word of the sentence.

If the same adjective appeared in the middle of a sentence, it would normally be lowercase:

Ця західна дорога довга = This western road is long

It would only be capitalized in special cases, such as part of an official name or title.

Two sounds often stand out to English speakers:

• х in західна is like the sound in Scottish loch or German Bach
• г in дорога and довга is usually a voiced h-like sound, not the hard English g

So the sentence will not sound like an English-style g in go.

A rough pronunciation guide is:

za-khid-na do-ro-ha dov-ha

That is only approximate, but it helps with the main consonants.

The subject is дорога = road.

More exactly:

• західна дорога = the noun phrase, western road
• довга = what is being said about it, long

So the sentence is built like this:

Subject: західна дорога
Predicate adjective: довга

That is why the sentence means The western road is long.