Learn Hardcore Finnish: Minäkin haluan osallistua kurssille, jos siellä on vielä tilaa. - I also want to participate in the course if there is still room.

Minäkin haluan = I also (I, too) want.
Haluankin osallistua = I do want to participate / actually, I want to participate (often corrective or confirming).
Kurssillekin haluan osallistua = I also want to take the course (in addition to something else). Write it as one word with its host: minäkin, not “minä kin”.

Why is osallistua in the infinitive instead of a conjugated form like osallistun?

Finnish uses the dictionary (1st) infinitive after verbs of desire/ability like haluan (I want), aion (I intend), voin (I can). So:

Haluan osallistua = I want to participate. Using a finite verb after haluan (e.g., “haluan osallistun”) is ungrammatical.

What case is kurssille, and what does it add?

Kurssille is allative (-lle), meaning “to/onto” a target. Here it conceptualizes the course as a destination or activity one joins: “to the course.”

Should it be kurssiin instead of kurssille after osallistua?

Traditionally, many style guides recommend the illative after osallistua (e.g., kilpailuun, kokoukseen, and for “course,” kurssiin). In everyday Finnish, however, kurssille is extremely common and perfectly idiomatic with activities like courses. You’ll hear both; if your teacher is strict about government, prefer illative (kurssiin). With other verbs, note:

ilmoittautua kurssille (register for a course) strongly prefers allative.

Why is it siellä and not sinne or siinä?

Siellä = “there (in/at that place)” for a static location; it fits with existence: siellä on (there is/are).
Sinne = “to there,” used with movement.
Siinä = “in that/at that (specific, near/just mentioned).” You could also be explicit: jos kurssilla on vielä tilaa (“if the course still has room”).

What does vielä mean here, and where does it go?

Vielä means “still / yet.” Placing it before what it modifies is most natural here: jos siellä on vielä tilaa. You might also hear jos siellä vielä on tilaa (slightly different emphasis).

Why is tilaa in the partitive instead of tila?

In existential sentences (there is/are), an uncountable or unspecified amount is in the partitive: siellä on tilaa = “there is (some) room/space there.” The nominative tila would imply a specific, clearly delimited unit and sounds odd in this context.

Do I need the comma before jos?

Yes. Finnish puts a comma between a main clause and a subordinate clause introduced by jos, että, koska, etc. If you front the jos-clause, you still use a comma:

Jos siellä on vielä tilaa, minäkin haluan osallistua kurssille.

Can I drop Minä?

Yes, Finnish often drops subject pronouns because the verb ending shows the person:

Haluan osallistua kurssille, jos siellä on vielä tilaa. To keep the “also” meaning without minäkin, use myös:
Haluan myös osallistua kurssille… (I also want to participate.)

Is haluan too direct? How can I sound more polite?

Haluan is direct and perfectly fine. For a softer, more polite tone, use conditional or modal expressions:

Haluaisin osallistua… (I would like to participate…)
Voisinko osallistua… (Could I participate…)
Olisin kiinnostunut osallistumaan… (I would be interested in participating…)

Could I rephrase the “there is room” part more explicitly?

Yes:

Jos kurssilla on vielä tilaa = “if the course still has room.”
As a question: Onko kurssilla vielä tilaa? = “Is there still room on the course?”

Can I change the word order for emphasis?

Some natural variants:

Haluan minäkin osallistua kurssille, jos siellä on vielä tilaa. (emphasizes “I, too”)
Minäkin haluan osallistua kurssille, jos tilaa vielä on. (focus on “room”) Avoid splitting osallistua unnaturally from its complement; keep osallistua kurssille together.

What’s the difference between -kin and myös for “also”?

-kin attaches to the exact element that is “also,” letting you focus: Minäkin haluan (I, too), Kurssillekin haluan (the course, too).
Myös is an adverb and is more neutral in placement: Haluan myös osallistua kurssille. Both are correct; -kin is great for fine-grained emphasis.

How would this sound in casual spoken Finnish?

A common colloquial version is:

Mäkin haluun osallistuu kurssille, jos siellä on viel tilaa. Notes: mä (minä), haluun (haluan), infinitive ending often reduced (osallistua → osallistuu in speech), viel (vielä). Use this in informal contexts only.