Viljen er stærk.

Because viljen is the definite form of the noun: the will.

• vilje = will
• viljen = the will

In Danish, instead of putting a separate word in front like English the, you often add the definite ending to the noun itself. For many common-gender nouns, that ending is -en.

So:

• en vilje = a will
• viljen = the will

Here, -en is the definite article ending for a common-gender noun.

Danish has two grammatical genders:

• common gender: usually takes en
• neuter gender: usually takes et

With a common-gender noun like vilje, the forms are:

• en vilje = a will
• viljen = the will

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

Because viljen is a common-gender singular noun, and after er the adjective stays in its basic form: stærk.

Compare:

• Viljen er stærk. = common gender singular
• Huset er stærkt. = neuter singular
• De er stærke. = plural

So the adjective changes depending on what it describes:

• common gender singular: stærk
• neuter singular: stærkt
• plural / definite contexts: stærke

Since viljen is common gender singular, stærk is correct.

Yes. Er is the present tense of at være (to be), and here it means is.

So the structure is very straightforward:

• Viljen = the will
• er = is
• stærk = strong

This is a very common Danish sentence pattern: subject + er + adjective

For example:

• Bogen er god. = The book is good.
• Maden er varm. = The food is warm.

Usually, Danish puts the definite article at the end of the noun instead of using a separate word before it.

So where English says:

• the car
• the book
• the will

Danish often says:

• bilen
• bogen
• viljen

This is one of the most important differences from English.

However, Danish can also use a separate definite word like den/det/de, but usually that happens when there is an adjective before the noun:

• viljen = the will
• den stærke vilje = the strong will

So in Viljen er stærk, no separate the-word is needed.

Grammatically, yes, but it means something different.

• Viljen er stærk. = The will is strong.
• En vilje er stærk. = A will is strong.

The second sentence sounds much less natural in most contexts, because it refers to a will in a general or indefinite sense. The original sentence sounds more like you are talking about a specific will, or about the will as a concept.

So if your intended meaning is the will is strong, then Viljen er stærk is the right choice.

It can often suggest willpower, depending on context.

The noun vilje can refer to:

• will in the sense of determination
• willpower
• desire / intention
• sometimes wish

So Viljen er stærk could feel a bit like:

• The will is strong
• The willpower is strong

The exact nuance depends on the broader context.

The normal word order here is:

subject + verb + adjective

So:

• Viljen = subject
• er = verb
• stærk = subject complement / adjective

This is the standard pattern for simple statements in Danish.

If you turn it into a question, the verb usually comes first:

• Er viljen stærk? = Is the will strong?

So Danish often switches to verb + subject in yes/no questions.

A rough guide is:

• viljen ≈ VIL-yen

A few points:

• v is like English v
• i is a short vowel here
• lj in Danish can be tricky; in normal speech it often sounds smoother than an English l+y sequence
• the ending -en in this word sounds like -en / -ən, often reduced in natural speech

If you want a practical learner-friendly approximation, VIL-yen is a decent start.

A rough English-friendly approximation is:

• stærk ≈ stairk, but with a more open Danish vowel

Important things to notice:

• æ is not exactly like English a in cat, but that is a useful starting point
• the r affects the vowel quality
• the final k is clearly pronounced

So if you say something close to stairk while keeping it short and crisp, you will be in the right area.

Then Danish usually uses double definiteness: a separate definite word plus the noun in a special form.

For example:

• viljen = the will
• den stærke vilje = the strong will

Notice what changes:

• you add den
• stærk becomes stærke
• the noun appears as vilje, not viljen

So:

• Viljen er stærk. = The will is strong.
• Den stærke vilje = The strong will.

That difference is very important in Danish grammar.