Learn Hardcore Finnish: Tämä aine on hyvä.

Putting aine after on (e.g. Tämä on aine hyvä) would sound strange or emphatic in a way that doesn’t match normal speech. Tämä aine belongs together as a noun phrase: this substance.

Why is aine in this sentence and not joku toinen sana (some other word)? What does aine really mean?

Aine is a general noun meaning:

substance, material, matter – in chemistry or physical sense
also subject, course material, essay in school contexts (e.g. ainekirjoitus = essay writing)

In this sentence, it’s most natural to understand it as substance / material, depending on the context (e.g. chemicals, materials science, medicine, etc.).

So Tämä aine on hyvä = This substance/material is good.

How do you pronounce ä in tämä and aine in general?

ä is a front vowel, similar to a in “cat” or “bad”, but usually a bit shorter and clearer.
Tämä is pronounced roughly: [ˈtæ.mæ]
aine is pronounced roughly: [ˈɑi.ne]
- ai = like English “eye”
- e = like “e” in “get”, never “ee”

Stress is always on the first syllable in Finnish: TÄ-mä, AI-ne.

Why is it tämä and not tämäN? I’ve seen tämän before.

Tämä is the nominative form (basic form) and is used for the subject of the sentence:
- Tämä aine on hyvä. – This substance is good.
Tämän is the genitive form (possessive / “of this”):
- Tämän aineen väri on kaunis. – The color of this substance is beautiful.

So you use tämä when it’s just this as the subject, and tämän when you need of this / this one’s.

Why is hyvä in the same form as aine? Shouldn’t it change?

In sentences with to be (olla), the complement (here: hyvä) usually agrees with the subject in number and case when we describe what something is:

Tämä aine (nominative singular)
hyvä (nominative singular to match the subject)

Other examples:

Auto on kallis. – The car is expensive.
Autot ovat kalliita. – The cars are expensive.

Here:

Tämä aine on hyvä. – singular, so hyvä (not hyviä).

Could it also be Tämä aine on hyvää? I’ve seen ruoka on hyvää before.

Yes, both can be used, but there’s a nuance:

Tämä aine on hyvä.
- hyvä (nominative) treats the substance as a whole, definite thing.
- More like evaluating this particular substance as good.
Tämä aine on hyvää.
- hyvää (partitive) treats it more as an indefinite mass or stuff.
- Often used with things you eat or drink (food, coffee, wine), or when focusing on the quality of the material rather than the individual item.

With ruoka and drinks, the partitive is very common:

Tämä ruoka on hyvää. – This food tastes good.

With aine, hyvä is probably more common unless you’re clearly talking about it as a mass substance (like a chemical) whose quality as a material is being evaluated.

Why doesn’t Finnish use any article like “a” or “the” in Tämä aine on hyvä?

Finnish simply has no articles (a, an, the).

The meaning of “this”, “that”, “some”, “the” etc. is expressed by:

demonstratives: tämä (this), tuo (that near you), se (that / it)
word order and context

So Tämä aine on hyvä can translate as:

This substance is good. (most natural)
There’s no need for a or the in Finnish.

What is on exactly? Does it always mean “is”?

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

olla – to be
minä olen – I am
sinä olet – you are
hän / se on – he / she / it is
me olemme – we are
te olette – you (pl.) are
he / ne ovat – they are

Here on means is (for this substance).

It can also correspond to “there is / there are” in existential sentences, but this sentence is just a normal is sentence.

Can on ever be left out, like sometimes “am / is / are” are dropped in informal English?

In standard written Finnish, on is not dropped in a sentence like this:

Tämä aine hyvä is incorrect in standard Finnish.

In certain colloquial spoken dialects, the verb olla may be reduced or merged with pronouns, but you should learn and use Tämä aine on hyvä as the normal, correct form.

What’s the difference between tämä, tuo, and se in similar sentences?

They all can be translated as “this / that / it”, but with different nuances:

tämä – this (here, near me)
- Tämä aine on hyvä. – This substance (near me) is good.
tuo – that (over there / near you)
- Tuo aine on hyvä. – That substance (near you / over there) is good.
se – that / it, often referring to something already known from context
- Se aine on hyvä. – That substance (we already mentioned / both know) is good.

In spoken language, se can sometimes replace tämä or tuo, but in careful language, the distance contrast is useful.

Could I say Tämä on hyvä aine instead, and does it mean the same thing?

Yes, you can say:

Tämä aine on hyvä. – This substance is good.
Tämä on hyvä aine. – This is a good substance.

They are very close in meaning, but there’s a slight difference in focus:

Tämä aine on hyvä emphasizes this particular substance and its quality.
Tämä on hyvä aine emphasizes this thing and classifies it as a good kind of substance.

Both are correct and natural; the context will often determine which sounds better.

Why is there no personal pronoun like “it” in Tämä aine on hyvä?

In Finnish, if the subject is already expressed (here: Tämä aine), you do not add an extra pronoun like English it:

English: This substance, it is good. (possible, though a bit redundant)
Finnish: Tämä aine on hyvä. (you cannot say Tämä aine se on hyvä in neutral style; that would be very emphatic or dialectal)

So:

Subject phrase: Tämä aine
Verb: on
No separate “it” needed.