Høreapparatet er lite.

Because -et is the definite ending for many neuter nouns in Norwegian.

• et høreapparat = a hearing aid
• høreapparatet = the hearing aid

So instead of using a separate word like English the, Norwegian often attaches the definite article to the end of the noun.

Because høreapparat is a neuter noun.

The adjective liten changes form depending on the gender and number of the noun:

• en liten bil = a small car
• et lite høreapparat = a small hearing aid
• små biler / små høreapparater = small cars / small hearing aids

In Høreapparatet er lite, the adjective has to agree with the neuter noun, so lite is correct.

The basic dictionary form is høreapparat.

You can think of its forms like this:

• et høreapparat = a hearing aid
• høreapparatet = the hearing aid
• høreapparater = hearing aids
• høreapparatene = the hearing aids

So in the sentence, you are seeing the singular definite form.

Yes. Norwegian very often makes compound nouns as a single word.

Here:

• høre relates to hearing
• apparat = device / apparatus

Together, høreapparat means hearing aid.

This is very normal in Norwegian. English often uses two words where Norwegian uses one.

Because in Norwegian, definiteness is often built into the noun itself.

Compare:

• et høreapparat = a hearing aid
• høreapparatet = the hearing aid

So høreapparatet already includes the idea of the. You do not need a separate word before it in this sentence.

It would be:

Et høreapparat er lite.

That means A hearing aid is small or The hearing aid is small, depending on context, though the most direct meaning is indefinite.

Compare:

• Et høreapparat er lite. = A hearing aid is small.
• Høreapparatet er lite. = The hearing aid is small.

No, this is a very basic Norwegian sentence pattern:

subject + verb + adjective

• Høreapparatet = subject
• er = is
• lite = small

So it works much like English The hearing aid is small.

Very often, yes. Er is the present tense of å være = to be.

Some useful forms are:

• å være = to be
• er = am / are / is
• var = was / were
• vært = been

So in this sentence, er simply means is.

Because lille is usually used in definite noun phrases with an adjective before the noun, not after er in this kind of sentence.

Compare:

• et lite høreapparat = a small hearing aid
• det lille høreapparatet = the small hearing aid
• høreapparatet er lite = the hearing aid is small

So:

• before the noun in a definite phrase: often lille
• after er: use the agreeing form lite

A learner-friendly guide would be something like:

HØ-re-ap-pa-RA-te

A few pronunciation notes:

• ø is a vowel sound that English does not really have
• the r is pronounced clearly in many varieties of Norwegian
• the word is made of several parts, so saying it slowly at first helps

Also, høre and øre are different words, so the h matters in spelling, even though pronunciation can vary by dialect.

Yes, but not in this sentence.

Here, lite is the neuter form of the adjective liten, meaning small.

But learners often confuse it with litt, which means a little.

Compare:

• Høreapparatet er lite. = The hearing aid is small.
• Jeg hører litt. = I hear a little.

So in your sentence, lite means small, not a little.