Belønningen er liten.

Because Norwegian usually puts the definite article on the end of the noun.

• belønning = reward
• belønningen = the reward

So the -en ending is doing the job that the does in English.

A useful extra point: if you put an adjective before the noun, Norwegian often uses both a separate article and the ending:

• den lille belønningen = the small reward

That is very normal in Norwegian.

In this sentence, the is already built into belønningen.

Norwegian often expresses definiteness with a suffix:

• en bil = a car
• bilen = the car

So Belønningen er liten literally works like Reward-the is small.

English learners often expect a separate word like the, but in many Norwegian sentences you do not need one.

Because liten agrees with a singular non-neuter noun in this sentence.

Here is the basic pattern for liten:

• liten = singular common gender
• lite = singular neuter
• små = plural
• lille = usually used before a definite noun

Examples:

• En bil er liten. = A car is small.
• Et hus er lite. = A house is small.
• Bilene er små. = The cars are small.
• den lille bilen = the small car

In Belønningen er liten, the adjective comes after er. That makes it a predicate adjective, and in that position you use liten/lite/små, not lille.

So:

• den lille belønningen = the small reward
• belønningen er liten = the reward is small

Yes, in Bokmål that can also be correct.

The noun belønning can be treated as:

• common gender / masculine-style: en belønning – belønningen
• feminine: ei belønning – belønninga

If you use the feminine form, the adjective can also take a feminine form:

• Belønninga er lita.

So both of these can be acceptable Bokmål:

• Belønningen er liten
• Belønninga er lita

The version in your sentence uses the common-gender/masculine-style pattern, which is very common in Bokmål.

Er is the present tense of å være, which means to be.

So:

• er = is / are / am, depending on context

In this sentence:

• Belønningen er liten. = The reward is small.

Some more examples:

• Han er glad. = He is happy.
• De er hjemme. = They are at home.

Norwegian does not change the verb for different persons the way English does. The form er stays the same:

• jeg er
• du er
• han er
• vi er

Yes, in this basic statement it is very similar:

• Belønningen = subject
• er = verb
• liten = adjective/complement

So the pattern is:

• subject + verb + adjective

That is very close to English:

• The reward is small.

But Norwegian also has the important verb-second rule. For example, if you make it a yes/no question, the verb comes first:

• Er belønningen liten? = Is the reward small?

And if another element comes first, the verb still stays in second position:

• I dag er belønningen liten. = Today the reward is small.

It can mean both, depending on context.

In many sentences, liten is best translated as small:

• Huset er lite. = The house is small.

But it can also correspond to little in English:

• en liten gutt = a little boy
• en liten pause = a little break / a short break

In Belønningen er liten, English would usually say small rather than little, although both may be understandable depending on context.

It can also refer to amount, importance, or value, not just physical size. So here it may mean that the reward is modest, not very large, or not worth much, depending on the situation.

The hardest part for many English speakers is ø.

• ø has no exact English equivalent.
• It is similar to the vowel in French deux or German schön if you know those languages.

A rough pronunciation guide:

• belønningen ≈ be-LØNN-ing-en
• liten ≈ LEE-ten

The main stress in belønningen is on the løn part.

A few pronunciation tips:

• ø is a rounded front vowel: your tongue is somewhat forward, and your lips are rounded.
• ng in belønningen is pronounced like the ng in sing.
• The final -en is usually light and unstressed.

Because ø is not native to English, it is best learned by listening and repeating rather than relying only on spelling.