Learn Hardcore Finnish: Valmentaja sanoi, että on parempi olla rento kuin liian jännittynyt. - The coach said that it is better to be relaxed than too tense.

Että is a conjunction that introduces a content clause (what was said, thought, etc.). It roughly corresponds to English “that” in sentences like “The coach said that…”.

Valmentaja sanoi, että… = The coach said that…
Without että, the sentence would feel incomplete or ungrammatical here, because Finnish normally needs that conjunction to introduce a full clause after sanoa, ajatella, luulla, etc.

You can occasionally drop että in very informal speech, but in standard written Finnish you should keep it:
Valmentaja sanoi, että on parempi olla rento kuin liian jännittynyt. ✔️

Why is it on parempi olla rento and not something like se on parempi olla rento? Where is the subject “it”?

In English we say “it is better to be relaxed”, using a “dummy it” that doesn’t really refer to anything.

Finnish does not need this dummy subject. Instead, the structure is:

on parempi = is better
olla rento = to be relaxed

So on here simply states existence of a general truth or evaluation. No pronoun like se is needed.

If you add se, as in että se on parempi olla rento, it sounds wrong because now se would need a real referent, which it doesn’t have. So the natural Finnish is:

että on parempi olla rento
not
että se on parempi olla rento ❌

Why is it olla rento and not olla rentona?

Rento is a predicate adjective after olla (“to be”), and the normal form there is the basic form (nominative):

Hän on rento. = He/She is relaxed.

So when you use the infinitive olla with a predicate adjective, you keep that same pattern:

olla rento = to be relaxed

Rentona is the essive case and is used in different kinds of expressions (state in which something is done), for example:

On tärkeää pysyä rentona. = It’s important to stay relaxed.
Harjoituksissa hän oli tosi rentona. = At practice, he/she was really relaxed.

In your sentence, it’s just a simple “to be X” pattern, so olla rento is correct.

Can I say on parempi olla rento kuin liian jännittyneenä instead of liian jännittynyt? What is the difference?

Both are understandable, but they’re not quite the same:

liian jännittynyt (past participle as an adjective, nominative)
- Functions like a regular adjective: too tense / too nervous.
- Fits directly into the pattern olla + adjective:
  - olla liian jännittynyt = to be too tense.
liian jännittyneenä (essive case)
- Emphasizes being in a state of being too tense: while in a too tense state.
- Feels a bit more like “when you are (in the state of) being too tense”.

In this sentence, the parallel structure:

olla rento
olla (liian) jännittynyt

is very clear and natural. So liian jännittynyt is the best and most neutral choice.

Why is it on parempi olla rento kuin liian jännittynyt, and not on parempi olla rento kuin liian jännittyneempi (a comparative form for jännittynyt)?

In Finnish (and English), the comparison here is not “more tense vs. less tense” but rather “relaxed vs. too tense”.

parempi olla rento kuin liian jännittynyt = better to be relaxed than too tense
The “better” belongs to the whole situation (being in state A vs. state B), not to the adjective jännittynyt itself.

If you said jännittyneempi, that would be “more tense”, and the structure would be odd:

on parempi olla rento kuin jännittyneempi ❌
- better to be relaxed than more tense — more tense than what?

So we keep parempi as the only comparative and use basic adjectives rento and liian jännittynyt to describe the two opposite states.

What is the function of kuin in this sentence? Is it always used with parempi?

Kuin is a comparative conjunction that roughly matches English “than”:

parempi kuin = better than
suurempi kuin = bigger than
nopeampi kuin = faster than

So the pattern here is:

on parempi olla rento kuin liian jännittynyt
= is better to be relaxed than (to be) too tense

Yes, when you compare two things with comparative forms (like parempi, suurempi, nopeampi), you normally use kuin to introduce the second item of the comparison.

Why is it Valmentaja sanoi, että on parempi… and not Valmentaja sanoo, että on parempi…? How do tenses work here?

Both are possible; they just describe different time frames:

Valmentaja sanoi, että on parempi olla rento…
- Past tense sanoi: the saying happened in the past.
- Present on: the content is still true now (a general rule).
Valmentaja sanoi, että oli parempi olla rento…
- Both in past: could suggest that it was better in that specific past situation.
Valmentaja sanoo, että on parempi olla rento…
- Present sanoo: the coach (still) says this regularly, or just now.
- Present on: the rule is presented as a general truth.

Finnish does not have a strict “sequence of tenses” rule like some languages. It’s quite natural to have sanoi + on when you want to say:
He said (earlier) that it is (still) better to be relaxed…

Could we say Valmentaja sanoi, että rento on parempi kuin liian jännittynyt? How would that change the meaning or style?

This alternative is grammatically possible:

Rento on parempi kuin liian jännittynyt.

However, it slightly shifts the focus:

on parempi olla rento kuin liian jännittynyt
- Focus on the state of being:
  - It is better *to be relaxed than (to be) too tense.*
rento on parempi kuin liian jännittynyt
- Sounds more like we’re comparing two adjectives or abstract qualities:
  - “Relaxed is better than too tense.”

Native speakers tend to prefer the olla + adjective infinitive pattern in this kind of advice, so the original is more idiomatic and natural.

Why don’t we see sinun (your) in the Finnish, as in “it’s better for you to be relaxed”?

English often includes an explicit “for someone”:

It’s better *for you to be relaxed…*

In Finnish this “you” is often implicit — understood from context. The sentence is a general rule or advice:

On parempi olla rento kuin liian jännittynyt.
= It is better to be relaxed than too tense (in general / for the person we are talking to).

If you want to make the subject explicit, you can:

Sinun on parempi olla rento kuin liian jännittynyt.
= It’s better for you to be relaxed than too tense.

But in many contexts (especially instructions, proverbs, general advice), Finnish leaves this subject out.

Why is there a comma before että in Finnish?

In Finnish punctuation, a comma is normally used before että when it starts a subordinate clause:

Valmentaja sanoi, että on parempi…
- Main clause: Valmentaja sanoi
- Subordinate (että-) clause: että on parempi olla rento kuin liian jännittynyt

So the comma visually separates the main clause from the content clause introduced by että. In standard writing this comma is required.

What is the difference between direct and indirect speech here?

The given sentence is indirect speech:

Valmentaja sanoi, että on parempi olla rento kuin liian jännittynyt.
= The coach said that it’s better to be relaxed than too tense.

The että-clause summarizes what was said, but doesn’t show the exact original wording.

Direct speech would look like this:

Valmentaja sanoi: “On parempi olla rento kuin liian jännittynyt.”
- You see exactly what the coach said, inside quotation marks.

Grammatically, the clause On parempi olla rento kuin liian jännittynyt itself is identical in both cases. The difference is mainly punctuation and whether you frame it as a quote or as reported content with että.

What does valmentaja mean exactly, and is it similar to opettaja?

valmentaja = coach (someone who trains, especially in sports, but also e.g. a life coach).
- From the verb valmentaa = to coach / to train.
opettaja = teacher (in school, university, courses, etc.).
- From opettaa = to teach.

So:

In a sports or performance context (like relaxation vs. tension), valmentaja is the natural word.
In a classroom/subject context, you would say opettaja instead.

What is the nuance difference between rento and rentoutunut in this kind of sentence?

Both describe a relaxed state, but they feel slightly different:

rento
- A general, often more permanent or usual characteristic:
  - Hän on rento tyyppi. = He/She is a relaxed type (easy-going person).
rentoutunut
- Literally “relaxed (as a result of relaxing)”; can sound more like a result state:
  - Hän on rentoutunut viikonlopun jälkeen.
    = He/She has become relaxed after the weekend.

In the sentence on parempi olla rento, rento feels more natural because the coach is talking about a general way or attitude to have during performance.
Rentoutunut would sound more like you have just relaxed from some earlier stress and are now in that result state; it’s less idiomatic in this exact proverb-like advice.