Learn Hardcore Finnish: Kielioppi on vaikeaa, mutta opettaja auttaa. - Grammar is difficult, but the teacher helps.

You’re talking about something in general, as a kind of “mass” or abstract thing.
You’re describing an open‑ended quality, not a specific, clearly bounded state.

So:

Kielioppi on vaikeaa. – Grammar is difficult (in general; as a subject, it’s hard).
Kielioppi on vaikea. – Also possible, but sounds more like this particular grammar is difficult, more concrete and specific.

Using vaikeaa here makes it sound like a general statement about grammar as a field being difficult, not just one particular bit of grammar.

What case is vaikeaa, exactly?

Vaikeaa is:

The partitive singular of vaikea (difficult).

Pattern:

vaikea → vaikeaa (partitive singular)

Adjectives often appear in the partitive when they are predicatives with olla and describe:

An indefinite or ongoing quality
Something abstract or “mass‑like”

That’s why you see vaikeaa here instead of the nominative vaikea.

What case is kielioppi, and what does that tell me?

Kielioppi is in the nominative singular.

It’s the subject of the sentence: Kielioppi (grammar) is what the sentence is talking about.
In basic “X is Y” sentences (X on Y), X is usually in the nominative.

So structurally:

Kielioppi (subject, nominative)
on (3rd person singular of olla)
vaikeaa (predicative adjective in partitive)

Why isn’t there any word for “the” in kielioppi or opettaja?

Finnish has no articles at all—no “a/an” and no “the”.

Kielioppi can mean “grammar”, “a grammar”, or “the grammar” depending on context.
Opettaja can mean “a teacher” or “the teacher”.

So:

Kielioppi on vaikeaa. → Grammar is difficult.
…mutta opettaja auttaa. → …but the teacher helps. (or a teacher helps, depending on what you mean)

The sense of definiteness is inferred from context, not from a separate word.

What’s the difference between mutta and vaan, both often translated as “but”?

Both can be translated as “but”, but they’re used differently.

mutta = but, however (general contrast)
vaan = but rather, but instead (used after a negation)

In your sentence:

Kielioppi on vaikeaa, mutta opettaja auttaa.
Grammar is difficult, but the teacher helps.
→ This is a simple contrast, so mutta is correct.

Examples with vaan:

Se ei ole helppoa, vaan vaikeaa. – It’s not easy, but rather difficult.
En ostanut omenaa, vaan banaanin. – I didn’t buy an apple but (instead) a banana.

Use mutta unless you’re explicitly “correcting” something after a negation; then use vaan.

Why is on used here, and what form of the verb is it?

On is the 3rd person singular present of the verb olla (to be).

The forms of olla in the present tense:

(minä) olen – I am
(sinä) olet – you are (singular)
(hän/se) on – he/she/it is
(me) olemme – we are
(te) olette – you are (plural / formal)
(he/ne) ovat – they are

In Kielioppi on vaikeaa, the subject kielioppi is 3rd person singular, so you use on (is).

Why is auttaa in that form? Isn’t that the dictionary form?

Yes, auttaa is both:

The dictionary form (1st infinitive), and
The 3rd person singular present form of the verb auttaa.

For many so‑called type 1 verbs (ending in -aa, -äa, -oa, -öä, -ua, -yä), the pattern is:

Dictionary form = stem + a/ä
3rd person singular present = same as the dictionary form

So:

auttaa → “to help” (dictionary form)
hän auttaa → “he/she helps” (3rd person singular)

In the sentence:

opettaja auttaa = the teacher helps
(opettaja is 3rd person singular, so auttaa is the correct finite form.)

Can I change the word order? For example, Opettaja auttaa, mutta kielioppi on vaikeaa?

Yes, you can.

Finnish word order is relatively flexible, and changing it mainly affects emphasis, not basic grammar.

Both are correct:

Kielioppi on vaikeaa, mutta opettaja auttaa.
– Neutral focus: Grammar is difficult, but the teacher helps.
Opettaja auttaa, mutta kielioppi on vaikeaa.
– Now the first focus is on “the teacher helps”, then you add the contrast about grammar.

Finnish tends to start the sentence with the element you want to highlight or anchor in the conversation, so word order is partly about what’s new or important information.

Why is the object of auttaa missing? Shouldn’t it be “helps me/us”?

In Finnish, if the object is obvious from context, it’s often simply left out.

Opettaja auttaa. – The teacher helps (us / me).
The sentence doesn’t say explicitly who, but it’s naturally understood as the learners.

When you want to state the object explicitly, auttaa usually takes the partitive:

Opettaja auttaa minua. – The teacher helps me.
Opettaja auttaa opiskelijoita. – The teacher helps the students.

So the original sentence is just more general and context‑dependent, which is very normal in Finnish.

How do you pronounce kielioppi, vaikeaa, and opettaja?

Basic pronunciation tips:

Stress is always on the first syllable in Finnish.
Double vowels and consonants are long.

kielioppi

Syllables: kie‑li‑op‑pi
ie is a diphthong (one smooth sound, like “yeh” in one syllable).
pp is a long p, held slightly longer.

vaikeaa

Syllables: vai‑ke‑aa
ai is a diphthong like English “eye”.
Final aa is a long a, held longer than in English “car”.

opettaja

Syllables: o‑pet‑ta‑ja
tt is a long t.
j is like the y in yes: ja ≈ ya.

All vowels are pure, not diphthongized like many English vowels.