Hún tekur ekki símann þegar hún er á vakt.

Yes — tekur is the 3rd person singular present form of taka, which basically means takes.

But in Icelandic, taka símann is a very common expression meaning to answer the phone or to pick up the phone. So this is one of those cases where the literal verb and the natural English translation are not exactly the same.

• taka = to take
• hún tekur = she takes
• hún tekur símann = she answers/picks up the phone

In a normal Icelandic main clause, the finite verb usually comes early in the sentence, and ekki typically comes after that finite verb.

So:

• Hún tekur ekki símann = literally She takes not the phone

That sounds strange in English, but it is normal Icelandic word order.

A useful pattern is:

• Subject + finite verb + ekki + ...

So here:

• Hún = subject
• tekur = finite verb
• ekki = not

Because símann is the object form with the definite article attached.

The base noun is:

• sími = phone

But after taka, the noun is a direct object, so it goes into the accusative case:

• síma = phone (accusative singular)

Then Icelandic adds the definite article -inn/-nn onto the end of the noun:

• símann = the phone (accusative singular)

So the chain is:

• sími → basic dictionary form
• síma → accusative
• símann → accusative + the

Because Icelandic usually expresses the as a suffix, not as a separate word like English does.

So instead of a separate word like the phone, Icelandic often says:

• símann = the phone

This attached article is very common in Icelandic:

• maður = man

• maðurinn = the man

• bíll = car
• bíllinn = the car

So símann is completely normal Icelandic structure.

Normally, no. Icelandic usually needs an explicit subject in each clause.

So in:

• Hún tekur ekki símann þegar hún er á vakt

there are really two clauses:

1. Hún tekur ekki símann
2. þegar hún er á vakt

The second clause still needs its own subject, so hún is repeated.

English does the same here:

• She doesn’t answer the phone when she is on duty

You would not normally say when is on duty.

Here þegar means when.

It introduces a time clause:

• þegar hún er á vakt = when she is on duty / when she is working a shift

In other contexts, þegar can sometimes have slightly different timing nuances depending on context, but here it is the ordinary temporal when.

Because after a conjunction like þegar, Icelandic normally uses subordinate-clause word order, where the subject comes before the verb.

So:

• þegar hún er á vakt = when she is on duty

That is the normal order:

• þegar = when
• hún = she
• er = is

This is different from the main-clause pattern where the finite verb often appears very early.

Á vakt is an idiomatic expression meaning on duty, at work, or on shift, depending on context.

Literally, it is something like on watch or on duty, but in natural English you would usually translate it as:

• on duty
• on shift

So:

• hún er á vakt = she is on duty / she is working a shift

This is a fixed expression, so it is best learned as a whole phrase.

Because á vakt is just the established idiomatic expression.

Prepositions do not always match English one-for-one, so even if English says on duty, at work, or on shift, Icelandic uses á here.

This is very common when learning Icelandic: the safest approach is often to memorize the whole phrase, not just the noun.

So learn:

• vera á vakt = to be on duty / to be on shift

It is in the present tense:

• tekur = takes
• er = is

But the meaning is probably habitual or general, not just about one exact moment.

So the sentence is likely saying something like this kind of general fact:

• she does not answer the phone when she is on duty
• whenever she is on shift, she does not pick up the phone

This is very normal use of the present tense in both Icelandic and English.

In a sentence like this, it often has a whenever sense in practice, even though the word itself is þegar = when.

Because the sentence is in the present tense and describes a repeated situation, many learners will understand it as:

• Whenever she is on duty, she doesn’t answer the phone

So the grammar says when, but the overall meaning can feel habitual: when/whenever.

By itself, it simply means she doesn’t answer/pick up the phone. It does not automatically tell you why.

The reason depends on context. It could mean:

• she is too busy
• she is not allowed to
• she chooses not to
• someone else is supposed to answer it

So the sentence states the fact, but not the motivation behind it.

Yes, taka símann is a very natural and common expression.

Even though the literal verb is take, learners should think of the whole phrase as a set expression:

• taka símann = answer the phone / pick up the phone

That kind of verb choice is just something you get used to in another language.