A szövetség erős.

In Hungarian, the verb to be is usually left out in the present tense, third person.

So:

• A szövetség erős. = The alliance is strong.

But in other persons, Hungarian does use the verb:

• Erős vagyok. = I am strong.
• Erős vagy. = You are strong.

This is one of the most important patterns in basic Hungarian sentences.

A is the Hungarian definite article, so here it means the.

Hungarian has two forms of the definite article:

• a
• az

The choice depends on the sound that follows:

• a before a consonant: a szövetség
• az before a vowel: az alma

So a szövetség means the alliance.

Because erős is not directly modifying the noun inside a noun phrase here; it is the predicate of the sentence.

Compare:

• az erős szövetség = the strong alliance
  
  • here erős comes before the noun because it directly describes it
• A szövetség erős. = The alliance is strong.
  
  • here erős comes after the noun because it is the main description in the sentence

So in this sentence, erős works like strong in The alliance is strong.

Yes, you could also say Erős a szövetség.

Both are grammatical, but the emphasis changes:

• A szövetség erős. = neutral statement
• Erős a szövetség. = puts more focus on strong

Hungarian word order is often influenced by focus and emphasis, not just grammar. So the two versions are close in meaning, but they do not sound exactly the same in tone.

A rough guide:

• sz is pronounced like English s in see
• s by itself is pronounced like English sh
• ö and ő are front rounded vowels, similar to German ö
• é is like a long ay sound, but pure and steady

So:

• szövetség sounds roughly like suh-vet-shayg or sö-vet-shayg
• erős sounds roughly like eh-rősh

Also, Hungarian stress is usually on the first syllable of each word:

• SZÖvetség
• Erős

The accent marks are important. They are not optional.

In this sentence:

• é marks a long vowel
• ő also marks a long vowel, and it is a different vowel from plain o or ö

So:

• e and é are different
• ö and ő are different in length
• changing them can change pronunciation and sometimes meaning

In Hungarian, vowel length matters, so it is worth learning to notice and write these marks carefully.

It is in the nominative case, which is the basic dictionary form.

Here, szövetség is the subject of the sentence:

• A szövetség erős.

There is no special ending on it because it is simply the subject.

No. Hungarian does not have grammatical gender like he/she/it agreement in adjectives.

So erős can describe:

• a masculine noun
• a feminine noun
• a neuter idea

The adjective itself does not change for gender.

This is usually much simpler for English speakers than languages such as German or French.

Yes, in a plural sentence the predicate adjective is normally plural too.

For example:

• A szövetség erős. = singular
• A szövetségek erősek. = plural

So:

• szövetség → szövetségek
• erős → erősek

Hungarian does not mark gender, but number does matter here.

In normal everyday Hungarian, that would usually sound unnatural for this meaning.

If you mean the alliance is strong, the normal form is:

• A szövetség erős.

Leaving out the article might only work in very special styles, such as headlines, slogans, notes, or very unusual emphasis. For a learner, it is best to use the article here.

Not only. Szövetség can be used in several kinds of contexts, such as:

• political alliance
• military alliance
• federation
• association
• alliance in a broader or figurative sense

The exact English translation depends on context. But grammatically, in this sentence, it behaves just like any other singular noun.