Learn Hardcore Finnish: Mitä enemmän juon kahvia illalla, sitä enemmän minua väsyttää aamulla. - The more I drink coffee in the evening, the more tired I feel in the morning.

Mitä enemmän juon kahvia illalla
= The more I drink coffee in the evening
sitä enemmän minua väsyttää aamulla
= the more tired I feel in the morning (literally: the more it makes me tired in the morning)

The pattern is:

Mitä + comparative/adverb,
sitä + comparative/adverb

Some more examples:

Mitä nopeammin kävelet, sitä nopeammin olet perillä.
The faster you walk, the sooner you arrive.
Mitä vähemmän nukun, sitä huonommin voin.
The less I sleep, the worse I feel.

So yes, Mitä enemmän ..., sitä enemmän ... is the standard Finnish way to say “the more ..., the more ...”.

Why is it mitä and sitä, and not something like kun or just enemmän juon ... enemmän väsyttää ...?

Mitä and sitä are part of a fixed correlative comparative construction.

mitä here is not a question word; it’s the partitive form of mikå (“what / which”), used in these comparisons.
sitä is the partitive form of se (“it / that”), matching the same pattern.

You can think of it very literally as:

Mitä enemmän ...
[That] what more ... → the more ...
sitä enemmän ...
that (in partitive) more ... → the more ...

You cannot replace mitä with kun here; kun would just mean “when” or “as”, and you would lose the special “the more..., the more...” meaning.

The structure without mitä/sitä:

✗ Enemmän juon kahvia illalla, enemmän minua väsyttää aamulla.

is ungrammatical/natural only in very marked, poetic styles. In normal Finnish the mitä – sitä pair is required.

Why is kahvia in the partitive case instead of kahvi?

Kahvia is the partitive singular of kahvi (“coffee”), and it’s used here for two main reasons:

Unspecified amount / “some coffee”
With verbs like juoda (to drink), the partitive is used for an indefinite, uncounted amount:
- Juon kahvia. = I drink coffee / I’m drinking some coffee.
- Juon kahvin. = I drink the coffee (the whole specific cup/portion).
In this sentence, we’re talking generally about how much coffee (increasing amount), not one specific, bounded cup.
Compatibility with “more/less” type meanings
The idea is about quantity rather than a single, whole object. The partitive is the “default” for partial, ongoing, or unbounded quantities.

So:

Mitä enemmän juon kahvia illalla
literally: The more I drink (some) coffee in the evening...
not “the more I drink *the coffee in the evening”*.

Why is it minua väsyttää and not minä väsyttää or olen väsynyt? What is going on with minua?

Minua väsyttää is a very typical impersonal feeling construction in Finnish.

Case of “minua”
- minua is the partitive form of minä (“I”).
- In this pattern, the experiencer (the person who feels something) is in the partitive, not in the nominative.
The verb “väsyttää”
- väsyttää is a transitive/causative verb: literally “to tire (someone), to make someone tired”.
- So minua väsyttää literally means:
  “It tires me / something makes me tired.”
  Idiomatic English: “I feel tired / I’m sleepy.”
Who is the subject?
Grammatically, the sentence is impersonal:
- The verb väsyttää is in 3rd person singular, with no explicit subject.
- The “thing” that makes you tired is implied (e.g., the coffee, the lack of sleep, etc.), and you appear in the partitive (minua).

Other similar patterns:

Minua janottaa. – I’m thirsty. (literally: It makes me thirsty.)
Minua paleltaa. – I’m cold. (literally: It makes me feel cold.)
Minua ärsyttää. – I’m annoyed / It annoys me.

So minua väsyttää is the natural Finnish way to express “I feel tired/sleepy” in many contexts, using this impersonal “it tires me” structure.

What is the difference between minua väsyttää and olen väsynyt? Can I use them interchangeably here?

Both can often be translated as “I’m tired,” but there is a nuance:

minua väsyttää
- Focuses on the current feeling of sleepiness/tiredness.
- It often suggests something is making you tired right now (lack of sleep, too much coffee at night, etc.).
- Very common for momentary or coming-on tiredness:
  Nyt minua väsyttää. – Now I feel (getting) tired.
olen väsynyt
- Literally: “I am tired.”
- Describes your state as an adjective (väsynyt = tired).
- Can sound a bit more static / general, like describing your condition:
  Olen tosi väsynyt. – I’m really tired (in general / overall).

In the given sentence, you could say:

Mitä enemmän juon kahvia illalla, sitä väsyneempi olen aamulla.

This is also correct and means:

The more coffee I drink in the evening, the more tired I am in the morning.

The original:

... sitä enemmän minua väsyttää aamulla.

sounds slightly more like “the more sleepy I feel in the morning”, emphasizing the feeling itself. Both are natural; the verb väsyttää just matches nicely with a cause-effect idea.

Why do we say illalla and aamulla with -lla, and what exactly do they mean?

Illalla and aamulla are in the adessive case (ending -lla/-llä), which has several uses. One of its idiomatic uses is to express time-of-day “at / in the X”:

aamulla – in the morning / at morning
päivällä – in the daytime / in the afternoon
illalla – in the evening
yöllä – at night

So in the sentence:

juon kahvia illalla – I drink coffee in the evening.
minua väsyttää aamulla – I feel tired in the morning.

You don’t normally say “illassa” or “aamussa” for this meaning; the adessive forms aamulla, päivällä, illalla, yöllä are the standard, almost fixed expressions for times of day.

Can I change the word order, for example to Mitä enemmän illalla juon kahvia, sitä enemmän minua väsyttää aamulla? Does it change the meaning?

Yes, you can change the word order quite freely in Finnish, and the basic meaning stays the same, though the focus/emphasis may shift slightly.

All of these are grammatical and natural:

Mitä enemmän juon kahvia illalla, sitä enemmän minua väsyttää aamulla.
Mitä enemmän illalla juon kahvia, sitä enemmän minua väsyttää aamulla.
Mitä enemmän kahvia illalla juon, sitä enemmän minua väsyttää aamulla.

Rough nuances:

Version 1 (original): neutral, very natural.
Version 2: puts illalla slightly more in focus: As for the evening, the more I drink coffee then...
Version 3: emphasizes kahvia a bit more: The more coffee I drink in the evening...

Because Finnish marks roles via cases, word order is relatively flexible compared with English. As long as the Mitä ... and sitä ... parts remain clear and the verb is in a logical place, the sentence remains understandable.

Can I leave out minua and just say sitä enemmän väsyttää aamulla?

Yes, especially in spoken Finnish, it’s quite common to omit the pronoun, when it’s clear from context who is being talked about.

For example, spoken style:

Mitä enemmän juon kahvia illalla, sitä enemmän väsyttää aamulla.

This effectively means the same as:

Mitä enemmän juon kahvia illalla, sitä enemmän minua väsyttää aamulla.

The experiencer (“me / you / one”) is understood from context. This kind of omission is very frequent with these impersonal feeling verbs:

Väsyttää. – (I’m) tired.
Janottaa. – (I’m) thirsty.
Paleltaa. – (I’m) cold.

In careful or written Finnish, including minua keeps the sentence explicit and is the safer choice for learners:

... sitä enemmän minua väsyttää aamulla.

Why is it sitä enemmän and not sen enemmän? What does sitä agree with?

Sitä is the partitive form of se (“it / that”).

Finnish often uses partitive with quantities and comparisons, and enemmän (“more”) is a quantity word that naturally combines with partitive:

enemmän vettä – more water
enemmän rahaa – more money
enemmän sitä – more of that

In this correlative pattern, mitä and sitä pair up:

mitä – partitive of mikå
sitä – partitive of se

So:

Mitä enemmän ... – the more (of something) ...
sitä enemmän ... – the more (of that) ...

Sen enemmän would use the genitive form sen, which does not fit this standard comparative construction. In these “the more..., the more...” sentences, Finnish specifically uses partitive: mitä – sitä.

How would I say “The less coffee I drink in the evening, the more tired I am in the morning” using the same pattern?

You just swap enemmän (“more”) for vähemmän (“less”) in the first part, and you can keep enemmän / väsyneempi etc. in the second. One natural version:

Mitä vähemmän juon kahvia illalla, sitä väsyneempi olen aamulla.
= The less coffee I drink in the evening, the more tired I am in the morning.

Another possibility, keeping minua väsyttää:

Mitä vähemmän juon kahvia illalla, sitä enemmän minua väsyttää aamulla.
= The less coffee I drink in the evening, the more (sleepy) I feel in the morning.

General patterns:

Mitä vähemmän X, sitä vähemmän Y. – The less X, the less Y.
Mitä vähemmän X, sitä enemmän Y. – The less X, the more Y.

What is a very literal word‑for‑word breakdown of Mitä enemmän juon kahvia illalla, sitä enemmän minua väsyttää aamulla, and why is the present tense used even though it’s about “in the morning”?

Word-by-word gloss:

Mitä – (partitive) what / which → here: the more that...
enemmän – more (comparative of paljon)
juon – I drink (1st person singular, present)
kahvia – coffee (partitive singular: some coffee)
illalla – in the evening (adessive)
sitä – (of) that / it (partitive of se)
enemmän – more
minua – me (partitive of minä)
väsyttää – tires / makes (someone) tired (3rd person singular)
aamulla – in the morning (adessive)

A very literal translation:

“What (the) more I drink coffee in the evening, that (the) more it tires me in the morning.”

Idiomatic English:

“The more I drink coffee in the evening, the more tired I am in the morning.”

About the present tense:

Finnish often uses the present tense to talk about general truths, habits, and repeated situations, where English might use present simple or some conditional-like reading.
Here, present tense juon / väsyttää describes a general rule / habitual pattern, not just one specific evening and morning.

If you wanted to talk about a single future event in English (“will be tired tomorrow morning”), Finnish would still normally use present, with a time expression:

Jos juon tänään paljon kahvia illalla, minua väsyttää huomenna aamulla.
Literally: If I drink a lot of coffee this evening, I (will) feel tired tomorrow morning.

No separate future tense is needed; context and time words carry the future meaning.