Vi ser en slange i skogen.

Because ser is the present tense form of the verb å se (to see).

A quick mini-paradigm:

• å se = to see
• ser = see / sees / am seeing / are seeing
• så = saw
• har sett = have seen

So Vi ser is simply we see or we are seeing.

Yes. In Norwegian, the present tense often covers both the simple present and the present progressive that English separates.

So Vi ser en slange can mean:

• We see a snake
• We are seeing a snake

Usually the context tells you which sounds more natural in English.

Because slange is a noun that takes the indefinite article en in Bokmål.

In singular indefinite form, Norwegian uses:

• en for many common-gender nouns
• et for neuter nouns

So:

• en slange = a snake

This is something you usually have to learn together with the noun: en slange.

Because Norwegian usually marks definiteness by adding an ending to the noun.

So:

• skog = forest
• skogen = the forest

That -en at the end works like English the here.

This is very common in Norwegian:

• en bil = a car
• bilen = the car

Because they are being treated differently in the sentence.

• en slange = an unspecified snake
• skogen = the forest, a specific or contextually understood place

So the sentence presents a snake but places it in the forest.

This kind of mix is completely normal in Norwegian, just as it is in English:

• We see a snake in the forest.

Here i means in.

So:

• i skogen = in the forest

It is the normal preposition for being located within an area or place. In English, in the forest is also often understood more generally, not necessarily deep inside it.

Because i is the normal choice for being in a forest.

• i skogen = in the forest

The preposition på is used for other kinds of locations, such as surfaces, islands, and some set place expressions. But for a forest, i is the natural choice.

So Vi ser en slange i skogen is the normal phrasing.

In this sentence, the word order is very similar to English:

• Vi = subject
• ser = verb
• en slange = object
• i skogen = place expression

So it follows a straightforward pattern:

Subject + Verb + Object + Place

That said, Norwegian has an important rule called V2 word order in main clauses, where the verb is usually in the second position. This sentence already fits that rule naturally.

Yes. That is also correct.

If you move I skogen to the front, Norwegian keeps the finite verb in second position:

• Vi ser en slange i skogen.
• I skogen ser vi en slange.

Notice that you do not say I skogen vi ser en slange in a normal main clause. The verb ser has to stay in second position.

Because vi is the subject form of we.

• vi = we
• oss = us

In this sentence, we are doing the action, so Norwegian uses vi:

• Vi ser ... = We see ...

You would use oss when us is the object:

• Han ser oss. = He sees us.

It is formed by adding the definite ending -en:

• skog = forest
• skogen = the forest

This is one of the most important noun patterns in Norwegian. Very often, you can think like this:

• indefinite base form: skog
• definite singular: skogen

So instead of putting a separate word before the noun, Norwegian often attaches the definite marker to the noun itself.

It is singular.

You can tell because of en:

• en slange = a snake

If it were plural, it would look different. For example:

• slanger = snakes

So Vi ser en slange means we see one snake.

A simple English-friendly approximation is:

• slange ≈ SLAH-nguh
• skogen ≈ SKOO-g'n

A few helpful notes:

• sl in slange is pronounced as a real s + l
• the a in slange is broad, not like the a in cat
• skog has a long oo-like vowel
• the final -en in skogen is often pronounced lightly

Exact pronunciation varies a bit by dialect, but those approximations are a good start.