Kantingen før velten er vanskelig.

Because Norwegian usually marks the definite form by adding the article to the end of the noun.

• en kanting = an/the edging

• kantingen = the edging

• en velt = a topple / a capsize
• velten = the topple / the capsize

So instead of a separate word like English the, Norwegian often uses a suffix.

The dictionary forms are:

• en kanting
• en velt

What you see in the sentence are the definite singular forms:

• kantingen
• velten

So if you wanted to look them up, you would normally search for kanting and velt.

Not in the same way as in English grammar. Here, kanting is a noun, not a verb form in the sentence.

That means kantingen behaves like a regular noun:

• it can be definite
• it can be the subject of the sentence
• it can take endings like -en

So although it looks similar to English -ing, in this sentence it is functioning as a thing/event/action noun, not as a present participle.

Here før means before and works as a preposition.

It is followed by a noun phrase:

• før velten = before the capsize / before the topple

So the structure is:

• kantingen = the edging
• før velten = before the capsize

Together, før velten describes which kanting is being talked about.

Because the definiteness is already built into velten.

• velt = topple/capsize
• velten = the topple / the capsize

So før velten already means before the capsize. You do not need a separate word for the.

Because vanskelig is used predicatively here, after er.

In Norwegian, adjectives often have one form when they come before a noun and another pattern when they come after a verb like er.

Here:

• Kantingen før velten er vanskelig.

The adjective comes after er, so it is describing the subject predicatively.

Also, vanskelige would usually be used for:

• plural: De er vanskelige
• or before a definite noun: den vanskelige kantingen

So:

• den vanskelige kantingen = the difficult edging
• kantingen er vanskelig = the edging is difficult

Er is the present tense of å være (to be).

So the sentence uses a very common pattern:

• [subject] + er + [adjective]

Examples:

• Boken er interessant.
• Oppgaven er vanskelig.

Here:

• Kantingen før velten = subject
• er = is
• vanskelig = difficult

The whole subject is Kantingen før velten.

That noun phrase contains:

• the main noun: kantingen
• a phrase modifying it: før velten

So the sentence is not just about kantingen in general, but specifically about the edging before the capsize.

Yes. Før can introduce either:

1. a noun phrase

   • før velten = before the capsize

2. a clause

   • før båten velter = before the boat capsizes

So in your sentence, før is followed by a noun phrase, not a full clause.

You would normally put ikke after the verb:

• Kantingen før velten er ikke vanskelig.

That is the standard position in a main clause:

• subject + verb + ikke
  • rest

Yes, but that would not be the same sentence type.

• Kantingen før velten er vanskelig. = a full sentence: The edging before the capsize is difficult.
• Den vanskelige kantingen før velten = a noun phrase: the difficult edging before the capsize

This is a useful contrast:

• predicative adjective: er vanskelig
• attributive adjective: den vanskelige ...

So Norwegian changes the adjective form depending on whether it comes after the verb or before the noun.