Das Kind verhält sich ruhig.

verhält sich comes from the verb sich verhalten, which means to behave or to conduct oneself.

It appears as two parts because:

• verhält = the conjugated verb form
• sich = the reflexive pronoun

So in this sentence, Das Kind verhält sich ruhig means that the child behaves in a calm/quiet way.

A useful thing to remember is that sich verhalten is a fixed reflexive verb. You normally learn it together with sich, not just as verhalten by itself in this meaning.

Because sich verhalten is a reflexive verb in German.

German often uses reflexive verbs where English does not. English says:

• The child behaves calmly.

German says:

• Das Kind verhält sich ruhig.

The sich refers back to the subject, das Kind. In English, the idea is somewhat like behaves itself, although normal English usually just says behaves.

The reflexive pronoun changes depending on the subject:

• ich verhalte mich
• du verhältst dich
• er/sie/es verhält sich
• wir verhalten uns
• ihr verhaltet euch
• sie/Sie verhalten sich

verhält is the 3rd person singular present tense form of sich verhalten.

The infinitive is:

• sich verhalten

The present-tense forms are:

• ich verhalte mich
• du verhältst dich
• er/sie/es verhält sich
• wir verhalten uns
• ihr verhaltet euch
• sie/Sie verhalten sich

Notice the vowel change:

• verhalten → verhält / verhältst

This kind of stem-vowel change is common in some German verbs.

Because Kind is a neuter noun in German.

Its article is:

• das Kind = the child

German nouns have grammatical gender, and Kind happens to be neuter, even though a child is a person.

So:

• das Kind = correct
• der Kind = incorrect

Other forms are:

• ein Kind = a child
• die Kinder = the children

Because ruhig is not directly describing the noun Kind here. It is describing how the child behaves.

So in this sentence, ruhig functions like an adverb in English: calmly/quietly.

German often uses the basic adjective form where English would use an adverb ending in -ly.

Compare:

• ein ruhiges Kind = a calm/quiet child
  Here ruhiges describes the noun Kind, so it takes an ending.

• Das Kind verhält sich ruhig. = The child behaves calmly/quietly.
  Here ruhig describes the action/behavior, so it has no ending.

This is a very common pattern in German.

It can suggest either one, depending on context.

ruhig often has meanings such as:

• calm
• quiet
• peaceful
• composed

In Das Kind verhält sich ruhig, the most natural English translation could be:

• The child is behaving calmly.
• The child is behaving quietly.

If the situation is about noise level, quietly may fit better.
If the situation is about emotional control or orderly behavior, calmly may fit better.

So the exact shade of meaning depends on the context.

Yes, you can say Das Kind ist ruhig, but it does not mean exactly the same thing.

• Das Kind ist ruhig = The child is calm/quiet.
  This describes the child’s state or quality.

• Das Kind verhält sich ruhig = The child behaves calmly/quietly.
  This focuses more on the child’s behavior in a situation.

So ist ruhig is more about what the child is like at that moment, while verhält sich ruhig emphasizes conduct or manner of behaving.

In many contexts they may overlap, but they are not identical.

The sentence follows normal German main-clause word order:

• Das Kind = subject
• verhält = finite verb
• sich = reflexive pronoun
• ruhig = adverbial adjective

So the structure is:

• Subject + verb + reflexive pronoun + adverbial

German main clauses usually put the finite verb in the second position:

• Das Kind verhält sich ruhig.

If you move another element to the front, the verb still stays in second position:

• Heute verhält sich das Kind ruhig.

And in a subordinate clause, the conjugated verb goes to the end:

• ..., weil sich das Kind ruhig verhält.

No. In this meaning, verhalten is inseparable.

That means the prefix ver- does not split off.

So you say:

• Das Kind verhält sich ruhig.

not:

• Das Kind hält sich ruhig ver. ✗

This matters especially when you compare it with truly separable verbs in German.

Also, in subordinate clauses, the verb stays together at the end:

• ..., weil sich das Kind ruhig verhält.

They are similar, and both can often be translated as to behave, but they are not always identical.

• sich verhalten is a bit more neutral or descriptive.
• sich benehmen can sometimes sound more like to behave oneself, especially in everyday speech or when talking about manners.

For example:

• Das Kind verhält sich ruhig.
  = The child is behaving calmly/quietly.

• Das Kind benimmt sich gut.
  = The child is behaving well.

So sich verhalten fits very naturally when you want to describe the manner of behavior, such as ruhig, vorsichtig, merkwürdig, and so on.

The main things that change are the verb form and the reflexive pronoun.

Examples:

• Ich verhalte mich ruhig. = I behave calmly.
• Du verhältst dich ruhig. = You behave calmly.
• Er verhält sich ruhig. = He behaves calmly.
• Wir verhalten uns ruhig. = We behave calmly.
• Ihr verhaltet euch ruhig. = You all behave calmly.
• Die Kinder verhalten sich ruhig. = The children behave calmly.

This is a good sentence pattern to memorize:

• [subject] + verhalten + reflexive pronoun + ruhig

For example:

• Die Schüler verhalten sich ruhig.
• Der Hund verhält sich ruhig.