Learn Hardcore Finnish: Illalla selkää särkee, koska olin laiska. - In the evening my back aches because I was lazy.

With many verbs of feeling, pain, or sensation, Finnish uses the partitive to mark the body part that is affected. This construction is impersonal in form but personal in meaning. So:

Selkää särkee. ≈ The back aches / My back aches.
Päätä särkee. ≈ (My) head hurts.
Kurkkua kivistää. ≈ (My) throat is sore.

Using the nominative (selkä särkee) would sound wrong or at least very odd in standard Finnish. The partitive here signals an indefinite, affective experience rather than a simple “back = subject” relationship.

Who is the subject of selkää särkee? Why is there no I / my?

Grammatically, selkää is not the subject; it’s an object-like argument in the partitive case. The verb särkeä is used impersonally here, so there is no explicit subject like “I” or “my back”.

You understand from context that it means “my back hurts”, but structurally Finnish is doing something like:

Selkää särkee. – There is aching to (the) back.
Päätäni särkee. – There is aching to my head.

If you want to make it explicitly “my”, you can add a possessive ending:

Selkääni särkee. – My back aches.

Still, the verb form remains third person singular and impersonal; Finnish doesn’t say “I ache my back”.

Can I say minun selkäni särkee instead of selkää särkee?

You can hear forms like minun selkäni särkee, but they have a different feel and are less idiomatic for pain.

More natural patterns are:

Selkää särkee. – very common, neutral.
Minun selkääni särkee. – adds explicit “my”.
Selkääni särkee. – also common: “my back hurts.”

Finnish normally prefers:

partitive of the body part + impersonal verb, possibly with a possessive ending:
- Päätä särkee. / Päätäni särkee.
- Jalkaa särkee. / Jalkaani särkee.

Minun selkäni särkee is technically grammatical, but for describing pain it sounds a bit less natural and more like you’re treating the back as a simple, definite subject rather than a locus of sensation.

Why is it Illalla selkää särkee and not something like Illallani selkää särkee if it means “in the evening my back hurts”?

Illalla is the adessive singular of ilta (evening). The adessive is used for time expressions meaning “at X time”:

Illalla – in the evening
Aamulla – in the morning
Yöllä – at night
Viikonloppuna – on the weekend

There’s no need to add any possessive to the time expression. You’re just saying “at evening / in the evening”, not “at my evening”.

Possessive endings like -ni usually mark ownership or a close relation, not “my point in time”. So illallani would be strange or at least very stylistic/poetic in everyday language.

Why is illalla at the beginning of the sentence? Can I say Selkää särkee illalla?

Yes, you can say Selkää särkee illalla. Word order in Finnish is relatively flexible.

Putting Illalla first does a few things:

Emphasises when it happens: As for the evening… the back hurts.
Sounds very natural as a topic–comment structure: first the time, then what happens at that time.

Both are grammatical:

Illalla selkää särkee. – In the evening, (my) back hurts.
Selkää särkee illalla. – The back hurts in the evening. (slightly more neutral emphasis)

The choice is mostly about focus and style, not correctness.

Why is särkee in the present tense if olin is in the past tense? Is it OK to mix tenses like that in Finnish?

Yes, this is a very normal and natural tense combination in Finnish.

Illalla selkää särkee – describes what typically/regularly happens in the evening (present tense with a habitual meaning).
koska olin laiska – explains the past cause of that present situation: because I was lazy (earlier / before that evening).

So the idea is something like:

“In the evening my back (generally) hurts, because earlier I was lazy.”

You could also keep everything in the present:

Illalla selkää särkee, koska olen laiska. – …because I am lazy.

Or everything in the past, describing one specific evening:

Illalla selkää särki, koska olin laiska. – In the evening my back hurt because I was lazy.

But as given, the mix is fine and very idiomatic: a present result explained by a past state/behaviour.

Does olin laiska mean “I was a lazy person in general” or “I behaved lazily that time”?

Context decides, but in a sentence like this, olin laiska is most naturally read as:

I was lazy (about exercise / posture / moving around) at that time.

So it usually points to lazy behaviour in that relevant period, not necessarily a permanent personality trait.

Compare:

Olen laiska. – I am lazy (as a general trait).
Olin laiska tänään. – I was lazy today (I didn’t do much).

In your sentence, we understand that the speaker didn’t do whatever would have prevented back pain (stretching, moving, maintaining posture), so now the back hurts.

What is the nuance difference between laiska and verbs like laiskotella or olla laiska liikkumaan?

laiska – an adjective: lazy. Can describe a general trait or temporary state:
- Olen laiska. – I’m lazy.
- Olen tänään laiska. – I’m lazy today.
laiskotella – a verb: to laze around, to lounge, to idle:
- Laiskottelin koko päivän. – I lazed around all day.
olla laiska + -maan/-mään – to be lazy (about doing X):
- Olen laiska liikkumaan. – I’m lazy about exercising.
- Olen laiska siivoamaan. – I’m lazy about cleaning.

Your sentence:

koska olin laiska

stays general and short: because I was lazy. You could make it more explicit:

koska olin laiska liikkumaan – because I was lazy about moving/exercising.
koska laiskottelin koko päivän – because I lazed around all day.

Could I say Illalla minua särkee selkään? Does that work?

That sounds odd and unidiomatic. With särkeä and similar pain verbs, Finnish prefers:

[partitive body part] + särkee – Selkää särkee, päätä särkee, polvea särkee…

The structure minua särkee selkään tries to use minua (partitive of “I”) as an experiencer, but this is not the normal pattern with särkeä.

More natural alternatives for “In the evening I have back pain”:

Illalla selkää särkee. – default.
Illalla selkääni särkee. – explicitly “my back”.
Illalla minulla on selkä kipeä. – lit. “In the evening I have a sore back.”

What is the difference between selkää särkee and minulla on selkä kipeä?

Both express pain, but with different structures and nuances:

Selkää särkee.
- Verb: särkeä (to ache).
- Construction: impersonal verb + partitive body part.
- Very compact and idiomatic for pain and headache:
  - Päätä särkee.
  - Selkää särkee.
Minulla on selkä kipeä.
- Literally: At me is back sore.
- Uses:
  - minulla on – possession/experiencer phrase.
  - selkä – body part (subject-like).
  - kipeä – adjective “sore, in pain”.

Nuance:

Selkää särkee. – tends to focus more on the ache itself.
Minulla on selkä kipeä. – a bit more like “I have a sore back”, describing a state.

Both are perfectly natural; usage depends a bit on personal style and the exact feeling you want to convey.