Learn Hardcore Finnish: Ajattelen, että suomi on joskus haastava, mutta juuri siksi se on kiinnostava. - I think that Finnish is sometimes challenging, but for that very reason it is interesting.

Ajattelen, että suomi on joskus haastava.
- Ajattelen = main clause
- että suomi on joskus haastava = subordinate clause introduced by että

So any time you have a structure like "Main clause + että + sentence", you put a comma before että:

Luulen, että hän tulee. – I think that he is coming.
Tiedän, että se on vaikeaa. – I know that it is difficult.

What exactly does että mean here, and how is it used?

Here että means “that” in the sense of introducing a content clause (what you think, know, say, etc.).

Structure:

ajattelen, että X = I think that X
luulen, että X = I believe that X
tiedän, että X = I know that X
sanon, että X = I say that X

In this sentence:

Ajattelen, että suomi on joskus haastava
= I think (that) Finnish is sometimes challenging.

In English, “that” is often omitted (I think Finnish is...), but in Finnish you normally keep että in this kind of sentence.

Why is there no minä in Ajattelen? How do I know it means “I think”?

Finnish usually omits subject pronouns because the verb ending already shows the person.

The verb ajatella (to think), present tense:

(minä) ajattelen – I think
(sinä) ajattelet – you think
(hän) ajattelee – he/she thinks
etc.

The -n ending in ajattelen tells you it’s 1st person singular (I), so minä is not needed.

You can say:

Minä ajattelen, että...

but it usually sounds like you’re emphasizing I, e.g. in contrast to someone else:
Minä ajattelen, että..., mutta sinä ajattelet, että...

Why is suomi not capitalized, even though “Finnish” is capitalized in English?

In Finnish, names of languages and nationalities are written with a lowercase letter, unlike in English.

So:

suomi = Finnish (language), Finnish (as a language name)
englanti = English
ruotsi = Swedish
saksa = German

In English:
I think *Finnish is sometimes challenging.
In Finnish:
Ajattelen, että suomi* on joskus haastava.

Both are correct in their own language’s capitalization rules.

Is suomi here “Finland” or “the Finnish language”? How do I say “the Finnish language” more explicitly?

Suomi can mean both “Finland” and “Finnish (the language)”, depending on context.

Here it clearly means the language, because it’s described as challenging and interesting, which are typical of languages, not countries.

If you want to be explicit, you can say:

suomen kieli – literally the language of Finnish

For example:

Ajattelen, että suomen kieli on joskus haastava.
= I think that the Finnish language is sometimes challenging.

Why is it "suomi on joskus haastava" and not "joskus suomi on haastava"? Is the word order fixed?

Both are grammatically correct, but the word order affects emphasis.

Default, neutral order:

Suomi on joskus haastava.
→ Slightly neutral/flat: Finnish is sometimes challenging.

If you say:

Joskus suomi on haastava.
→ You emphasize “sometimes” more: Sometimes Finnish is challenging (other times not).

In your sentence, suomi on joskus haastava is a natural, neutral statement. Finnish word order is fairly flexible, but putting the subject first is a common neutral choice.

What’s the difference between haastava and vaikea? Both seem to mean “difficult”.

Both can be translated as “difficult”, but the nuance is different:

vaikea = difficult, hard, troublesome
- Often neutral or negative: it’s just hard.
- Example: Tämä tehtävä on vaikea. – This task is difficult.
haastava = challenging
- Implies a challenge that can be interesting, demanding, maybe even positive.
- Often used for things that require effort but can be rewarding.
- Example: Työ on haastava, mutta palkitseva. – The work is challenging but rewarding.

In your sentence, haastava fits nicely with kiinnostava (interesting). It suggests: It’s hard, but in a good, stimulating way.

Why is it juuri siksi? What does this phrase do exactly?

Juuri siksi literally means “exactly for that reason” or “precisely because of that”.

siksi = for that reason, because of that
juuri = just, exactly, precisely (as an emphasizer)

So:

...mutta juuri siksi se on kiinnostava.
= ...but *exactly for that reason it is interesting.*

It links directly to what came before:

It’s sometimes challenging, and that challenge is exactly why it’s interesting.

You can sometimes move juuri:

mutta se on juuri siksi kiinnostava
= but it is interesting precisely because of that

The meaning is similar; the nuance of emphasis shifts slightly, but juuri siksi is a very common fixed phrase.

Why do we use se to refer back to suomi? Could we use hän?

For inanimate things and languages, Finnish uses se (“it”), not hän.

se = it / that (for things, animals, abstract concepts, languages)
hän = he / she (for people, and sometimes personified beings like God, Santa, pets in some styles)

So:

Suomi on joskus haastava, mutta juuri siksi se on kiinnostava.
= Finnish is sometimes challenging, but that’s exactly why *it is interesting.*

Using hän for suomi would sound strange or jokingly personified, like you’re treating the language as a person.

Why is it kiinnostava and not kiinnostavaa? I thought predicative adjectives often take partitive.

With olla (“to be”), adjectives describing the subject’s quality are usually in nominative singular if the subject is a countable, whole thing or a singular abstract concept.

Here:

suomi (the Finnish language) is treated as a single, whole entity.
So predicative adjectives are nominative:
- Suomi on joskus haastava.
- Suomi on kiinnostava.

You’d expect partitive (e.g. kiinnostavaa) when:

The subject is in partitive, or
You’re talking about only a part or some amount, or
The sentence has a more “incomplete / ongoing” nuance.

For example:

Opiskelu on joskus raskasta. (opiskelu can act more like an uncountable mass activity)
Se on vähän tylsää. – It is a bit boring. (partitive because of vähän and the “somewhat” feeling)

Here, suomi ... on kiinnostava is a clear, general, complete statement: Finnish is interesting. → nominative kiinnostava.

What’s the difference between kiinnostava and kiinnostunut?

This is a classic “-ing vs -ed” type difference:

kiinnostava = interesting (causes interest)
- Suomi on kiinnostava. – Finnish is interesting.
kiinnostunut = interested (feels interest)
- Olen kiinnostunut suomesta. – I am interested in Finnish.

So:

X on kiinnostava – X is interesting.
Olen kiinnostunut X:stä / X:sta – I am interested in X.

Could I say "Ajattelen suomen olevan joskus haastavaa" instead of using että?

Yes, that’s grammatically correct but more formal and less common in everyday speech.

Ajattelen, että suomi on joskus haastava.
→ Natural, neutral, very common.
Ajattelen suomen olevan joskus haastavaa.
→ More compact, written style, a bit more formal or literary.

Notes:

suomen olevan = “Finnish being”
Here haastavaa is partitive, which often appears in this nominative + infinitive construction; it can sound slightly more abstract or descriptive.

As a learner, prefer "Ajattelen, että..." in everyday language. The “suomen olevan” structure is good to recognize and use later for more advanced, formal writing.

Why do we use mutta here? Could we use vaikka instead?

In this sentence, mutta = “but” and contrasts two statements:

suomi on joskus haastava
juuri siksi se on kiinnostava

So:

mutta = but (simple contrast between two facts)
- Suomi on joskus haastava, mutta juuri siksi se on kiinnostava.

Vaikka means “even though / although” and normally introduces a subordinate clause, not simply link two main clauses in this way.

Examples:

Vaikka suomi on joskus haastava, se on kiinnostava.
= Even though Finnish is sometimes challenging, it is interesting.

So you cannot just replace mutta with vaikka and keep the rest the same:

✗ Suomi on joskus haastava, vaikka juuri siksi se on kiinnostava.
→ feels wrong: vaikka needs a different clause structure.

Here, mutta is exactly right: simple “but” linking two main clauses.

Is ajattelen, että... the usual way to say “I think that ...”? How is it different from minusta?

Both are used to express opinions, but they have slightly different flavors:

ajattelen, että... = I think that...
- Very close to English “I think that…”.
- Focuses on a mental process / conclusion.
- Example: Ajattelen, että suomi on joskus haastava.
minusta ... = in my opinion ... / to me ...
- Very common, often sounds more colloquial and natural for opinions.
- Structure: Minusta suomi on joskus haastava.
- Literally: From me Finnish is sometimes challenging → In my view, Finnish is sometimes challenging.

Both are correct. In speech, minusta is extremely common:

Minusta suomi on haastava, mutta kiinnostava.
Minun mielestäni suomi on haastava, mutta kiinnostava. (more formal/explicit: “in my opinion”)

Your sentence with ajattelen, että... is perfectly fine and clear.