Hon vill anteckna allt som sägs i mötesrummet.

Because vill is a modal verb. In Swedish, modal verbs such as vill, kan, ska, måste, får are normally followed directly by the infinitive, without att.

So:

• hon vill anteckna = she wants to take notes / write down
• not hon vill att anteckna

This is similar to English she wants to write, not she wants to to write.

Anteckna is the infinitive form of the verb, the basic dictionary form.

After vill, Swedish uses the infinitive:

• vill anteckna
• kan anteckna
• ska anteckna

The verb anteckna means to take notes, to note down, or to write down depending on context.

Allt is used because it means everything or all that, referring to things in a general, uncountable way.

Compare:

• allt = everything / all
• alla = all, when talking about plural countable nouns

Examples:

• allt som sägs = everything that is said
• alla böcker = all the books

So allt som sägs is the natural choice here because the sentence is talking about all spoken content, not a set of separate countable items.

Yes, allting is possible in many contexts and also means everything.

So Hon vill anteckna allting som sägs i mötesrummet is understandable and natural. However, allt is often a bit more compact and very common in this kind of sentence.

In many cases:

• allt = slightly more neutral and compact
• allting = also common, sometimes a little more emphatic or conversational

Here som is a relative word, equivalent to English that, which, or sometimes what in natural translation.

So:

• allt som sägs = everything that is said

It connects allt to the clause sägs.

This is a very common Swedish structure:

• boken som jag läser = the book that I am reading
• personen som kom = the person who came
• allt som händer = everything that happens

Because the sentence uses the passive.

• säger = says / are saying
• sägs = is said / gets said

So:

• allt som sägs = everything that is said

The focus is on the words being spoken, not on who is speaking them. That is why the passive works well here.

If you used säger, you would need a subject:

• allt som de säger = everything that they say
• allt som man säger = everything that one says / people say

But in the original sentence, the speaker is left unspecified.

It is the s-passive, a very common Swedish passive form.

The active present form is:

• säger = says / is saying

The passive present form is:

• sägs = is said

Swedish often makes the passive by adding -s to the verb form. This is simpler and more common than trying to build a passive with a separate verb, as English often does.

More examples:

• boken läses = the book is being read / is read
• dörren öppnas = the door is opened / opens
• det sägs att... = it is said that...

Because Swedish makes compound nouns very freely.

mötesrummet is built from:

• möte = meeting
• rum = room
• -et = the definite ending for a neuter noun

So:

• mötesrum = meeting room
• mötesrummet = the meeting room

English usually writes compounds like this as two words more often, but Swedish commonly writes them as one word.

Because the sentence refers to the meeting room, not just a meeting room.

Compare:

• ett mötesrum = a meeting room
• mötesrummet = the meeting room

In Swedish, definiteness is usually shown by adding an ending to the noun:

• ett rum = a room
• rummet = the room

So i mötesrummet means in the meeting room.

This often implies a specific room known from the situation or context.

Because i usually means in or inside, and here the idea is that the speaking happens inside the meeting room.

So:

• i mötesrummet = in the meeting room

That is the most natural preposition when talking about being physically inside a room.

Most naturally, it goes with sägs:

• allt som sägs i mötesrummet = everything that is said in the meeting room

In other words, it tells you where the speaking happens.

Of course, in a broader sense it affects the whole situation, but grammatically and semantically it is most closely connected with sägs.

Yes, some parts can move, especially adverbials like i mötesrummet. But Swedish still follows the usual verb-second rule in main clauses.

The original sentence:

• Hon vill anteckna allt som sägs i mötesrummet.

You could also say:

• I mötesrummet vill hon anteckna allt som sägs.

That is still correct, because vill remains the second element in the main clause.

However, inside the relative clause som sägs i mötesrummet, the order is more fixed and natural as it is.

Yes, very common.

It is a standard way to say everything that is ... plus a verb:

• allt som händer = everything that happens
• allt som behövs = everything that is needed
• allt som skrivs = everything that is written

So allt som sägs is a very natural and useful pattern to learn.