Katten ser rotta.

In Norwegian, the definite article is usually attached to the end of the noun instead of appearing as a separate word before it.

• katt = cat
• katten = the cat
• rotte = rat
• rotta = the rat

So Katten ser rotta literally works like cat-the sees rat-the, but in natural English that becomes The cat sees the rat.

The ending -en is the usual definite singular ending for many masculine/common-gender nouns in Bokmål.

• en katt = a cat
• katten = the cat

So katt is the base noun, and -en makes it definite.

Because rotte is often treated as a feminine noun in Bokmål, and many feminine nouns take -a in the definite singular.

• ei rotte = a rat
• rotta = the rat

However, Bokmål often allows feminine nouns to be treated as common gender too, so you may also see:

• en rotte
• rotten

So rotta and rotten can both be correct in Bokmål, depending on style and preference.

Ser is the present tense of the verb å se, which means to see.

• å se = to see
• ser = sees / see

So:

• Katten ser rotta = The cat sees the rat

No. In Norwegian, verbs do not change depending on the subject.

For example:

• jeg ser = I see
• du ser = you see
• katten ser = the cat sees
• vi ser = we see

This is simpler than English, where you have I see but he/she sees.

Yes. This sentence uses the normal Norwegian word order for a basic statement:

subject + verb + object

• Katten = subject
• ser = verb
• rotta = object

So:

• Katten ser rotta = The cat sees the rat

This is the standard word order in a simple main clause.

Because å se can take a direct object when you mean to see.

• Katten ser rotta = The cat sees the rat

If you use se på, it usually means look at rather than simply see.

• Katten ser på rotta = The cat is looking at the rat

So the version without på is the natural one for sees.

A rough English-friendly guide is:

• Katten ≈ KAHT-ten
• ser ≈ sehr
• rotta ≈ ROTT-ah

A few helpful points:

• The tt in katten and rotta means the vowel before it is short.
• The r in Norwegian is usually clearer than in most English accents.
• The e in ser is not like the English word see.

A more natural approximation would be something like:

KAHT-ten sehr ROTT-ah

Yes. Both are singular definite forms.

• katten = the cat (one cat)
• rotta = the rat (one rat)

If they were plural, the forms would be different.

Usually, Katten ser rotta is understood as The cat sees the rat.

If you want to clearly say is looking at, Norwegian normally uses ser på:

• Katten ser på rotta = The cat is looking at the rat

So the sentence you have is best understood as sees.

Because this sentence is definite, not indefinite.

• en katt = a cat
• ei rotte / en rotte = a rat
• katten = the cat
• rotta / rotten = the rat

So the sentence is specifically talking about the cat and the rat, not just any cat or rat.