Learn Hardcore Finnish: Siskoni haluaa näyttelijäksi ja käy nyt teatterikerhossa. - My sister wants to become an actor and now goes to a theatre club.

You could say minun siskoni (literally my my-sister), but in normal speech the minun is usually dropped unless you want to emphasize my in contrast to someone else’s:

Minun siskoni haluaa näyttelijäksi, ei sinun.
My sister wants to become an actress, not yours.

Can siskoni also mean my sisters?

Yes, siskoni is ambiguous:

siskoni can mean my sister (singular)
siskoni can also mean my sisters (plural)

Context decides which one is meant. In this sentence, English-speakers normally interpret it as singular (my sister), but Finnish grammar itself allows both readings.

To be very explicit about the plural, you could say:

siskoni = my sister / my sisters (ambiguous)
siskojeni = clearly my sisters (genitive plural + possessive suffix)

Why is it haluaa and not halua or haluan? What tense and person is this?

The verb is haluta (to want). Here it is conjugated:

haluan = I want
haluat = you (sg.) want
hän haluaa = he / she wants
haluamme = we want
etc.

In the sentence:

Siskoni haluaa… = My sister wants…

So haluaa is:

3rd person singular
present tense
matches siskoni (my sister) as the subject

It’s not halua, because Finnish present tense needs a personal ending.
It’s not haluan, because that would mean I want.

What case is näyttelijäksi, and why isn’t it just näyttelijä?

Näyttelijäksi is the translative case (ending -ksi).

Basic form:

näyttelijä = actor / actress

Translative:

näyttelijä + ksi → näyttelijäksi = into an actor / actress, to become an actor / actress

The translative case often expresses:

a change of state or role:
- tulla lääkäriksi = to become a doctor
- valita hänet puheenjohtajaksi = to choose him/her as chairperson

So haluaa näyttelijäksi literally means:

(she) wants (to be / to become) an actor/actress

If you said haluaa näyttelijä, it would be ungrammatical in this meaning; the change or target state needs the translative -ksi.

In English we would say “wants to be / to become an actress”. Why is there no verb like olla (to be) or tulla (to become) in haluaa näyttelijäksi?

Finnish often uses haluta + noun in translative instead of adding a separate to be / to become verb:

Siskoni haluaa näyttelijäksi.
Literally: My sister wants (into being) an actress.

This construction already implies “to be / to become” because the translative -ksi shows a desired goal or future role.
You could say:

Siskoni haluaa tulla näyttelijäksi. = My sister wants to become an actress.

Both are correct. The version without tulla is very natural and common in Finnish and a bit more compact.

What exactly does käy mean here, and why not use menee?

The verb is käydä, here conjugated as käy (he/she goes, visits, attends).

käydä usually means to go (and come back), to visit, to attend regularly.
mennä means simply to go (to a place), without the idea of a visit as an event or habit.

In this sentence:

käy nyt teatterikerhossa = (she) now attends a theatre club / drama club

So käy suggests:

regular, repeated activity (like attending a club, class, or group)
- käyn salilla = I go to the gym (regularly)
- käymme kurssilla = we attend a course

If you used menee:

menee teatterikerhoon = (she) goes to the theatre club (to, into it – a single movement)

That would focus more on the motion to the place, not on the idea of attending as a hobby.

Why isn’t the subject repeated before käy? Shouldn’t it be Siskoni haluaa… ja hän käy nyt…?

In Finnish, when two verbs share the same subject and are joined with ja (and), the subject often appears only once:

Siskoni haluaa näyttelijäksi ja käy nyt teatterikerhossa.
= My sister wants to become an actress and now attends a theatre club.

Adding hän is possible but less natural in this simple sentence:

Siskoni haluaa näyttelijäksi ja hän käy nyt teatterkerhossa.

You’d usually add hän only for emphasis or to avoid confusion, for example if the second verb had a different subject.

What does nyt mean here? Is it “right now” or “these days / nowadays”?

Nyt normally means now, but context decides whether it’s:

right now, at this moment, or
nowadays / at this point in her life

In this sentence:

…ja käy nyt teatterikerhossa.
Very naturally reads as “and (she) now attends a theatre club” in the sense of currently / these days, maybe as a new or recent activity.

You could emphasize “nowadays” more explicitly with:

…ja käy nykyään teatterikerhossa.
(nykyään = nowadays)

What case is teatterikerhossa, and what does the -ssa ending mean?

Teatterikerhossa is in the inessive case, marked by -ssa / -ssä, which usually means in, inside, at.

Breakdown:

teatterikerho = theatre club / drama club
teatterikerho + ssa → teatterikerhossa = in the theatre club / at the theatre club

So:

käy teatterikerhossa = goes to / attends a theatre club (literally: visits in the theatre club)

Compare with other local cases:

teatterikerhoon (illative, -oon) = into the theatre club (movement into)
teatterikerhosta (elative, -sta) = out of / from the theatre club

Here the inessive -ssa suits the idea of being at / attending that place.

Why is teatterikerho one word and not written as teatteri kerho?

Finnish loves compound words: two nouns are often glued together to form a single new noun.

teatteri = theatre
kerho = club
→ teatterikerho = a club whose theme is theatre (theatre club / drama club)

Writing teatteri kerho as two words would be wrong here and would look like two separate nouns placed next to each other without forming a proper compound.

Other examples:

kielikurssi (kieli + kurssi) = language course
työpaikka (työ + paikka) = workplace
jalkapallojoukkue (jalkapallo + joukkue) = football team

Why are there no articles like a or the in the Finnish sentence?

Finnish does not have articles at all. There is no direct equivalent of English a / an / the.

So:

Siskoni haluaa näyttelijäksi
can be translated as My sister wants to become an actress (with an in English), even though Finnish just uses the bare noun.
teatterikerhossa
can mean in a theatre club or in the theatre club, depending on context. Finnish leaves that generic/specific distinction to context instead of grammar.

Is the word order fixed? Could I say Nyt siskoni haluaa näyttelijäksi ja käy teatterikerhossa?

Finnish word order is relatively flexible, and changes mainly affect emphasis, not basic grammar.

Original:

Siskoni haluaa näyttelijäksi ja käy nyt teatterikerhossa.

Possible variants:

Nyt siskoni haluaa näyttelijäksi ja käy teatterikerhossa.
Emphasizes now: Now it is that my sister wants to become an actress and attends a theatre club (as opposed to earlier).
Siskoni käy nyt teatterikerhossa ja haluaa näyttelijäksi.
Emphasizes the attending as the first mentioned fact.

All are grammatically possible. The given order is a very neutral, natural way to present who, what she wants, and what she is doing now to work toward that goal.

Could you break the whole sentence down word for word?

Yes:

Sisko = sister
-ni = my
→ Siskoni = my sister
haluaa = wants (3rd person singular, present tense of haluta)
näyttelijä = actor / actress
-ksi = translative case (into, to become)
→ näyttelijäksi = to (become) an actor/actress
ja = and
käy = goes, visits, attends (3rd person singular, present tense of käydä)
nyt = now / currently
teatteri = theatre
kerho = club
→ teatterikerho = theatre club / drama club
-ssa = inessive case (in, at)
→ teatterikerhossa = in / at the theatre club

So the whole sentence:

Siskoni haluaa näyttelijäksi ja käy nyt teatterikerhossa.
= My sister wants to become an actress and now attends a theatre club.