Learn Hardcore Finnish: Kun keskittyminen katoaa, nousen hetkeksi ylös ja venyttelen. - When my concentration disappears, I get up for a moment and stretch.

kun = when (in a temporal or conditional sense)
- Kun keskittyminen katoaa = When (whenever) concentration disappears
koska = mainly because in modern Finnish
- En tee sitä, koska olen väsynyt. = I’m not doing it because I’m tired.

In older or very formal language, koska can sometimes mean when, but in today’s everyday Finnish, for a time-based when, you almost always use kun.

So here, we’re talking about a situation that happens whenever something occurs, so kun is the natural choice.

What kind of word is keskittyminen, and why isn’t the verb keskittyy used instead?

Keskittyminen is a noun, not a verb. It’s an action noun formed with -minen from the verb keskittyä (to concentrate).

keskittyä = to concentrate
keskittyminen = concentration, the act of concentrating

The structure is:

Kun keskittyminen katoaa
When (the) concentration disappears

If you wrote kun keskittyy, that would be a verb:

Kun keskittyy, jaksaa paremmin.
When one concentrates, one has more stamina.

That sentence uses an impersonal/“generic you” subject. Our sentence, however, treats concentration as a thing (a noun) that disappears, so the noun form keskittyminen is required.

The English translation is “When my concentration disappears…”, but there is no minun in the Finnish Kun keskittyminen katoaa. How is my expressed?

In Finnish, possessive pronouns like minun (my) are often left out when the possessor is obvious from context, especially when it’s the subject of the sentence.

Here, the person who reacts (nousen, venyttelen) is clearly I, so it’s understood that the concentration is my concentration.

More explicit versions would be:

Kun keskittymiseni katoaa, nousen…
(my concentration; possessive suffix -ni)
Kun minun keskittymiseni katoaa, nousen…
Very explicit and a bit more formal/emphatic.

In everyday speech, the simple Kun keskittyminen katoaa… is completely natural, and “my concentration” is understood from context.

In katoaa, what verb is this, and why does it look like that? How does it relate to kadota?

The basic verb is kadota = to disappear, to vanish.

Its present tense forms (indicative) include:

minä katoan
sinä katoat
hän katoaa
me katoamme
te katoatte
he katoavat

In the sentence we have katoaa:

keskittyminen katoaa = concentration disappears

So:

kadota (dictionary form) → stem kato- in the present tense
3rd person singular ending is -aa, giving katoaa

This is a regular pattern for verbs like this in Finnish; the spelling change from d to t and the long aa is just how the present tense is formed from kadota.

Why is kadota / katoaa used here instead of something like häviää or menee pois? Do they mean the same thing?

All of these can be related to “disappearing”, but they have slightly different nuances:

kadota = to disappear, vanish
Neutral, very common for things that stop being present or can’t be perceived.
häviää (from hävitää / hävitä)
- can mean to disappear, but also to lose (a game) or to be lost.
- Avaimet hävisivät. = The keys disappeared / got lost.
mennä pois = literally to go away, more concrete motion.

For concentration fading away, kadota is the most natural, neutral choice:

Kun keskittyminen katoaa… = When concentration disappears…

Using menee pois would sound more colloquial and physical, and häviää would be understood, but it carries extra meanings not needed here.

Why is the subject pronoun minä not written before nousen and venyttelen? How do we know it means I?

Finnish doesn’t need subject pronouns the way English does, because the person is marked in the verb ending.

nousen = I get up (1st person singular)
venyttelen = I stretch (1st person singular)

So:

(Minä) nousen hetkeksi ylös ja venyttelen.

Adding minä is possible, but usually only for emphasis or contrast:

Minä nousen hetkeksi ylös ja venyttelen.
(Implying: I do this, as opposed to someone else.)

In neutral statements, it’s completely natural to drop minä and rely on the verb ending.

What is the role of ylös in nousen hetkeksi ylös? Doesn’t nousta already mean “to get up”?

Nousta means to rise, to get up, to stand up, but Finnish often adds direction words to make movement more specific:

nousta ylös = get up / stand up (literally rise up)
nousta pois = get up and away / get off (e.g. from a seat)
nousta ylös sängystä = get up out of bed

Here, nousen hetkeksi ylös sounds very natural and idiomatic, like English “I get up for a moment” or “I stand up for a bit”.

You could also say just:

Nousen hetkeksi ja venyttelen.

That’s still correct. Ylös just emphasizes the upward movement of standing up.

Why is it hetkeksi and not hetki or hetken? What does the ending -ksi do?

Hetkeksi is the translative case of hetki (a moment).

hetki (nominative) = a moment
hetken (genitive) – often used adverbially as “for a moment”
hetkeksi (translative) – here: for a (short) while / for a moment

The translative -ksi is commonly used to express duration: “for (a period of time)”:

tunniksi = for an hour
päiväksi = for a day
viikoksi = for a week
hetkeksi = for a moment / for a short while

So:

Nousen hetkeksi ylös = I get up for a short while.

You could say hetken instead (Nousen hetken ylös), but hetkeksi is more typical in this kind of “I’ll do X for a bit and then stop” context, emphasizing it’s a temporary state.

What does the ending -elen in venyttelen mean? How is venyttelen different from venytän?

Venyttelen comes from the verb venytellä, which is a frequentative/iterative form of venyttää:

venyttää = to stretch (something), transitive
- Venytän jalkoja. = I stretch my legs.
venytellä = to do some stretching, to stretch around, often oneself, casually or repeatedly
- Venyttelen. = I (do some) stretching.

The ending -ele- / -ele- (here -tele- / -ttele- / -telle- by sound changes) often indicates:

repeated, gentle, or casual action
doing something here and there, not just once

So venyttelen (1st person singular) suggests:

I stretch a bit / here and there / casually, not one single big stretch.

That fits very well with the idea of getting up for a short break from work.

Why is there no object after venyttelen? Should it be venyttelen itseäni or venyttelen lihaksia?

With venytellä, the object is often understood and doesn’t need to be said, especially when you’re talking about stretching your own body.

Venyttelen.
→ naturally understood as “I stretch (my body / muscles).”

If you want to be more specific, you can add an object:

Venyttelen jalkoja. = I stretch my legs.
Venyttelen hartioita. = I stretch my shoulders.
Venyttelen itseäni. = I stretch myself (grammatically fine, but not the most natural everyday choice).

In this context, venyttelen alone is idiomatic and clear.

Is the comma before nousen required in Finnish? What is the rule with kun clauses?

Yes, the comma is required here.

In standard Finnish punctuation, a subordinate clause introduced by kun is separated from the main clause by a comma:

Kun keskittyminen katoaa, nousen hetkeksi ylös ja venyttelen.

This is true whether the kun-clause comes first or second:

Kun keskittyminen katoaa, nousen hetkeksi ylös.
Nousen hetkeksi ylös, kun keskittyminen katoaa.

So: kun = starts a subordinate clause → that clause is set off with a comma from the main clause.

Could the word order be Kun katoaa keskittyminen, nousen…? Would that change the meaning?

You can say Kun katoaa keskittyminen, but the nuance changes.

Kun keskittyminen katoaa…
Neutral subject–verb order; keskittyminen (concentration) is presented as the topic (what we’re talking about), and katoaa is a statement about it.
Kun katoaa keskittyminen…
More marked; it sounds like you’re emphasizing the event katoaa (disappears), and keskittyminen comes in as new or contrastive information.
Roughly: “When there disappears the concentration…”

In everyday neutral speech, Kun keskittyminen katoaa… is more natural and standard. The alternative word order isn’t wrong, but it carries a different emphasis.

All the verbs are in the present tense: katoaa, nousen, venyttelen. How does Finnish express the idea of “whenever this happens, I do X” with the present tense?

Finnish uses the simple present tense both for:

actions happening right now, and
habitual or repeated actions (what you “do in general”).

So:

Kun keskittyminen katoaa, nousen hetkeksi ylös ja venyttelen.
Literally: When concentration disappears, I get up for a moment and stretch.
Interpreted as: Whenever my concentration disappears, I (usually) get up for a moment and stretch.

There is no separate “simple present vs. present continuous” distinction like in English. Context tells you whether the sentence describes:

a single, current event, or
a general habit / rule / routine.

Here, it clearly describes a general strategy or habit, so native speakers automatically read it that way.