Hon vill volontera i sommar.

No. Vill is the present tense of vilja, and it means want or wants to.

So:

• Hon vill volontera = She wants to volunteer
• English future will is not Swedish vill

Swedish often expresses future in other ways, for example with:

• ska
• kommer att
• the simple present together with a time expression

That is why vill is a very common false friend for English speakers.

Because after a modal verb like vill, Swedish normally uses the infinitive without att.

Common modal verbs include:

• vill = want to
• kan = can
• ska = will / am going to / should
• måste = must
• får = may / get to

So you say:

• Hon vill volontera
• Jag kan simma
• Vi måste gå

Not:

• Hon vill att volontera

It is understandable, but it can sound a bit newer or English-influenced. Many Swedish speakers would more naturally say:

• volontärarbeta
• jobba som volontär
• vara volontär

So this sentence is understandable, but if you want a very safe, natural option, you could also say:

• Hon vill volontärarbeta i sommar
• Hon vill jobba som volontär i sommar

No. Swedish verbs do not change for person.

So you get:

• Jag vill
• Du vill
• Hon vill
• Vi vill
• De vill

The verb form vill stays the same. That is much simpler than English.

The dictionary form is vilja, which means to want.

Important forms are:

• infinitive: vilja
• present: vill
• past: ville
• supine: velat

So in this sentence, vill is the present-tense form.

I sommar means this summer or in the summer / during the summer, depending on context.

Swedish often uses i in time expressions like these:

• i sommar
• i vinter
• i år
• i veckan

Here, i means something like during / in.

A useful comparison:

• i sommar = this coming summer / during this summer
• på sommaren = in summer, generally or habitually

So Hon vill volontera i sommar points to a specific summer period, not summers in general.

Grammatically, vill is present tense. But the action of volunteering is understood as future because of i sommar.

That is very normal in Swedish. A present-tense verb can talk about the future when there is a time expression showing it clearly.

So the sentence means:

• she wants now
• to volunteer this summer

This is the normal word order for a simple main clause:

• subject: Hon
• finite verb: vill
• infinitive: volontera
• time expression: i sommar

Swedish main clauses follow the V2 rule, which means the finite verb comes in the second position.

So if you start with the subject, you get:

• Hon vill volontera i sommar

If you move the time expression to the front, the verb still stays second:

• I sommar vill hon volontera

That word order is very important in Swedish.

Yes, but the meaning changes.

• Hon vill volontera i sommar = she wants to volunteer this summer
• Hon ska volontera i sommar = she is going to / is supposed to / will volunteer this summer

So vill expresses desire, while ska expresses a plan, intention, or expectation.

Yes. That is a very natural alternative.

Compare:

• Hon vill volontera i sommar
• Hon vill vara volontär i sommar
• Hon vill jobba som volontär i sommar

These are all close in meaning, but the last two often sound more idiomatic to many Swedish speakers. If you are unsure, jobba som volontär is a very safe choice.