Learn Hardcore Finnish: Puhdistan maton heti, jos kahvi peittää sen kokonaan. - I clean the rug immediately if coffee covers it completely.

The verb puhdistan is the first person singular present tense form of puhdistaa (to clean).
- infinitive: puhdistaa
- 1st person singular: puhdistan → I clean / I will clean
Finnish usually does not use the subject pronoun (minä, sinä, etc.) when it’s clear from the verb ending:
- puhdistan already means I clean, so minä puhdistan is not necessary in neutral style.
- You can say minä puhdistan if you want to emphasize I, e.g. contrast: I will clean it, not you.
There’s no separate future tense in Finnish, so puhdistan can mean both:
- I clean the carpet (regularly)
- I will clean the carpet (on this occasion / in the future)
  Here, context tells us it means I will clean (in the future) if the condition is met.

Why is it “maton” and not “matto”?

Matto is the basic form (nominative singular) meaning “carpet, rug”.
Maton is the genitive/accusative singular form.

In this sentence, maton is the object of puhdistan:

puhdistan maton = I (will) clean the carpet (completely / as a whole).

Finnish uses the genitive/accusative form for a total object (the entire thing is affected and the action is seen as complete). Contrast:

Puhdistan maton. – I clean the (whole) carpet. (total object: maton)
Puhdistan mattoa. – I am (in the process of) cleaning (some of) the carpet. (partitive object: mattoa)

So maton here tells us that the whole carpet will be cleaned, not just partially.

What is the role of “heti” and can it be placed elsewhere?

Heti is an adverb meaning “immediately / right away”.
It modifies puhdistan: I’ll clean the carpet immediately.

Word order is fairly flexible in Finnish, so you might see:

Puhdistan maton heti, jos kahvi peittää sen kokonaan.
Heti puhdistan maton, jos kahvi peittää sen kokonaan. (slightly emphasizing immediately)

In neutral speech, the original position after the verb phrase is very common and natural. The meaning does not change significantly; moving heti just changes emphasis a bit.

Why is there a comma before “jos”?

In Finnish, you normally separate a subordinate clause from the main clause with a comma.

Puhdistan maton heti – main clause
jos kahvi peittää sen kokonaan – subordinate clause introduced by jos (if)

Rule of thumb: when you have jos, kun, koska, että, vaikka etc. starting a clause, you put a comma between that clause and the main clause:

Teen sen, jos ehdin. – I’ll do it, if I have time.
Tulen, kun olen valmis. – I’ll come when I’m ready.
Lähden, koska olen väsynyt. – I’m leaving because I’m tired.

What does “jos” mean exactly, and how is it different from “kun”?

Jos = “if”, used for conditional situations that may or may not happen.
Kun can mean “when” (in many contexts), and often suggests something more expected or certain.

In this sentence:

jos kahvi peittää sen kokonaan = if the coffee covers it completely
→ It might happen, or it might not.

If we changed jos to kun:

Puhdistan maton heti, kun kahvi peittää sen kokonaan.

This would sound like you are expecting the coffee to cover it (more like when that happens), which is odd unless you are describing a predictable event. So jos is the natural choice for a hypothetical spill.

Why is it “kahvi” and not “kahvia”?

Both forms exist, but they have different uses:

kahvi (nominative) here is the subject of the verb peittää.
- kahvi peittää = the coffee covers (like English treating “coffee” as a thing that does the action).
kahvia is the partitive form and would be used in other roles, for example:
- Jos kahvia kaatuu matolle, puhdistan sen heti.
  If (some) coffee spills onto the carpet, I’ll clean it immediately.

In the given sentence, we’re not talking about the act of spilling, but about the state where the coffee already covers the carpet, so kahvi acts as a normal subject: coffee covers it.

Why is it “peittää” and what form is that?

Peittää is the 3rd person singular present tense of peittää (same form as the infinitive in spelling, but here acting as a finite verb).
- infinitive: peittää = to cover
- 3rd person singular: hän peittää, kahvi peittää = he/she/it covers, the coffee covers

Because kahvi is singular (like the coffee as a whole mass), the verb is also singular:

kahvi peittää sen = the coffee covers it.

Like with puhdistan, the present tense in Finnish also covers future meaning:

jos kahvi peittää sen = if the coffee (ever) covers it → if the coffee covers it (in the future).

Why is the pronoun “sen” used, and what does it refer to?

Sen is the genitive/accusative singular form of se (it / that).
Here it refers back to matto (carpet).

So kahvi peittää sen = the coffee covers it (≈ the coffee covers the carpet).

Why not sitä?

Sitä is the partitive form of se and is used when:
- the object is partial/indefinite, or
- the action is ongoing, incomplete, or unbounded.

Here, peittää sen kokonaan clearly says that the carpet is covered completely (a total effect on the whole object), so sen (total object) fits, not sitä (partial object).

You can think:

peittää sen kokonaan – cover it completely (total)
peittää sitä – is covering it / is in the process of covering it (partial/ongoing)

What does “kokonaan” add to the sentence?

Kokonaan means “completely, entirely, wholly”.
It emphasizes that the coffee covers the entire carpet, not just a part of it.

Compare:

jos kahvi peittää sen – if the coffee covers it (could be partial or total, context decides)
jos kahvi peittää sen kokonaan – if the coffee covers it completely (explicitly total)

So kokonaan aligns with the total-object forms maton and sen: everything is affected fully.

Could you say “Jos kahvi peittää sen kokonaan, puhdistan maton heti” instead? Does that change the meaning?

Yes, that is perfectly correct:

Jos kahvi peittää sen kokonaan, puhdistan maton heti.

Finnish allows the subordinate clause to come either before or after the main clause:

Puhdistan maton heti, jos kahvi peittää sen kokonaan.
Jos kahvi peittää sen kokonaan, puhdistan maton heti.

The meaning is essentially the same.
Putting the “jos”-clause first can give it a little more prominence: it sets up the condition right away, but there is no grammatical or major semantic difference.

Why is the verb in the present tense when the English translation uses the future (“will clean”)?

Finnish generally does not have a separate future tense. The present tense is used also for future actions, and context disambiguates:

Huomenna siivoan. – Tomorrow I clean → I will clean tomorrow.
Puhdistan maton heti, jos kahvi peittää sen kokonaan.
→ I will clean the carpet immediately, if the coffee covers it completely.

So both puhdistan and peittää are present forms but express a future situation that depends on a condition.

Could you use “puhdistan sitä” instead of “puhdistan sen”? What would that mean?

In the given sentence, that would be odd and would change the meaning.

Puhdistan sen (maton). – I clean it / I will clean it (as a whole).
- sen = total object → the whole carpet is cleaned.
Puhdistan sitä. – I am (in the process of) cleaning it / I clean some of it.
- sitä = partitive object → partial or ongoing action, not necessarily reaching a completed end-state.

Since the condition is “if the coffee covers it completely” and the response is cleaning the carpet as a complete reaction, the total object form sen / maton is the natural choice. Using sitä would sound like you’re just describing an ongoing activity, not necessarily a full clean-up.

Is there any consonant gradation happening in “matto → maton”?

Yes. Finnish has consonant gradation, and matto shows it:

nominative singular: matto (strong grade tt)
genitive singular: maton (weak grade t)

So when matto is put into the genitive/accusative form as an object:

matto → maton

This is a normal pattern for many words with -tt- in the strong grade:

katto → katon
sukkato (sock, archaic type) → sukan etc.

In the sentence, maton is the weak-grade form used as a total object.