Learn Hardcore Finnish: Jos jokin tarkastus peruuntuu viime hetkellä, yritän olla menettämättä hermojani. - If some check-up is cancelled at the last moment, I try not to lose my nerve.

joku is mainly used about people (and sometimes about things in more colloquial speech).
- Joku tuli sisään. = Someone came in.
jokin is more typical with things, objects, abstract items, events.
- Jokin ääni kuului ulkoa. = Some (kind of) sound was heard from outside.

Here tarkastus is an event/thing (an inspection), not a person, so jokin tarkastus sounds more natural and a bit more formal/neutral than joku tarkastus.

You might hear joku tarkastus in speech, but jokin tarkastus is the textbook‑correct and stylistically better choice here.

What does tarkastus mean exactly? Is it “inspection”, “check”, or “exam”?

The noun tarkastus is based on the verb tarkastaa (“to check / to inspect / to examine”). Depending on context, tarkastus can mean:

an inspection (e.g. safety inspection, tax inspection)
a check (e.g. ticket check on a bus)
a review / examination of something

In this sentence, tarkastus is best understood as some kind of inspection or check, but the exact English word depends on the real‑world situation.

It does not usually mean a school exam (that would more often be koe or tentti).

What is the difference between perua and peruuntua?

They form a transitive–intransitive pair:

perua = to cancel something (you actively cancel it)
- Perun tapaamisen. = I cancel the meeting.
peruuntua = to be cancelled (it gets cancelled, without saying by whom)
- Tapaaminen peruuntui. = The meeting was cancelled.

In your sentence:

tarkastus peruuntuu = the inspection gets cancelled / is cancelled

So peruuntua is not a passive; it’s just an intransitive verb that describes the event of cancellation happening to the inspection itself.

Why is the verb in the jos clause in the normal present (peruuntuu) and not in a conditional form like peruuntuisi?

Finnish makes a clear difference:

Real / general condition (things that really can or do happen, including habitual situations):
- Jos jokin tarkastus peruuntuu, yritän …
  = If some inspection gets cancelled (whenever that happens in real life), I try …
Hypothetical / imagined condition (more “what if / suppose that”):
- Jos jokin tarkastus peruuntuisi, yrittäisin olla…
  = If some inspection were to get cancelled, I would try …

In your sentence, the speaker is talking about a real, recurring situation (“Whenever this happens, I try not to lose my temper”), so peruuntuu / yritän (present indicative) is the natural choice.

Why is the present tense yritän used even though this can refer to the future?

Finnish normally uses the present tense to talk about:

current actions or states
habitual / general actions
and very often future events as well

So:

Jos jokin tarkastus peruuntuu, yritän olla …
literally: If some inspection gets cancelled, I try to …
but contextually: If an inspection gets cancelled (in those moments / in the future), I try to …

You usually don’t need a special “will” construction in Finnish; the present tense is enough.

What does viime hetkellä literally mean, and why is -llä used?

viime = last
hetki = moment
hetkellä is hetki in the adessive case (-lla/-llä), which among other things means “at (some time)”.

So literally viime hetkellä = at the last moment.

The adessive -llä is commonly used for expressions of time:

keskipäivällä = at noon
yöllä = at night
viime hetkellä = at the last moment

So viime hetkellä is a direct idiomatic match to English “at the last minute / at the last moment”.

Could I move viime hetkellä to another position in the sentence?

Yes. Finnish word order is relatively flexible, so all of these are grammatically fine, with only small differences in emphasis:

Jos jokin tarkastus peruuntuu viime hetkellä, yritän olla menettämättä hermojani.
(neutral; “gets cancelled at the last moment” is just part of the event description)
Jos jokin tarkastus viime hetkellä peruuntuu, yritän olla menettämättä hermojani.
(slightly stronger focus on the timing of the cancellation)
Jos viime hetkellä jokin tarkastus peruuntuu, yritän olla menettämättä hermojani.
(special emphasis on “if it happens at the last moment”)

The original word order is the most natural, neutral‑sounding choice.

What is the structure yritän olla menettämättä? Why olla there?

The core meaning is “I try not to lose my temper.”

The structure is:

yritän = I try
olla menettämättä hermojani = “to be not losing my temper” → idiomatically, to not lose my temper

This is a common Finnish pattern:
yrittää + (olla) tekemättä = to try not to do (something)

Examples:

Yritän olla valittamatta. = I try not to complain.
Yritän olla syömättä liikaa. = I try not to eat too much.

Here olla menettämättä binds with the -mAtta form (menettämättä) to express “being in a state of not losing (it)”, which is the Finnish way of saying “not to lose” in such constructions.

What exactly is menettämättä? Is it some kind of infinitive?

Yes. menettämättä is the 3rd infinitive in the abessive case of the verb menettää (“to lose”).

Pattern:

3rd infinitive in -MA form: menettämä-
abessive ending: -ttä
→ menettämättä = without losing / not losing

This -mAtta form is used a lot in the pattern:

olla + verb-matta/-mättä = to be without doing, to not do (in that sense)
- yritän olla menettämättä = I try to be without losing → I try not to lose
- olin sanomatta mitään = I was without saying anything → I didn’t say anything (on purpose)

So menettämättä is the “without losing / not losing” form of menettää.

Why is it hermojani and not hermoni or hermon?

hermojani breaks down as:

hermo = nerve
hermot (plural) = nerves → idiomatically “one’s temper”
hermoja- = plural partitive stem
-ni = “my”

So hermojani = “my nerves” in partitive plural.

Two key points:

Idiom / meaning
In Finnish, the expression for “to lose one’s temper” is usually:
- menettää hermonsa (literally: “lose his/her nerves”)
  The plural hermot corresponds to the English singular “temper”.
Case: why partitive?
With the -mAtta form (menettämättä), the object verb typically appears in the partitive:
- syömättä ruokaa = without eating food
- sanomatta sanaakaan = without saying a word
- menettämättä hermojani = without losing my nerves / without losing my temper

So hermojani is required here by both the idiom (plural “nerves”) and the grammar of the -mAtta construction (partitive object).

Could I say menettämättä hermoja instead of hermojani?

Yes, but the nuance changes:

menettämättä hermojani = without losing *my temper*
menettämättä hermoja = without losing (any) nerves / without people losing their nerves / without nerves being lost (more generic or depersonalized)

If you want to clearly say “my temper”, you should keep -ni:

hermojani = my nerves (my temper)

Is there a reason for the comma between the two parts of the sentence?

Yes. The structure is:

Subordinate jos clause: Jos jokin tarkastus peruuntuu viime hetkellä
Main clause: yritän olla menettämättä hermojani.

In standard Finnish punctuation, a comma is used:

between a preceding subordinate clause and the following main clause
→ Jos …, yritän …

So the comma here is obligatory in written standard Finnish.

Can I drop jokin and just say Jos tarkastus peruuntuu viime hetkellä…?

Yes, that’s possible, but it changes the feel slightly:

Jos jokin tarkastus peruuntuu…
= If any inspection / if some inspection gets cancelled…
(unspecified, more general)
Jos tarkastus peruuntuu…
= If the inspection gets cancelled…
(sounds more like you’re talking about a particular inspection that is already known from context)

So:

For a general rule / habit, jokin tarkastus fits well.
For a specific, known inspection, tarkastus without jokin can be more natural.