Learn Hardcore Finnish: Oppitunti kestää neljäkymmentä minuuttia.

oppitunti – lesson, class period (literally something like learning hour: oppi = learning, tunti = hour)
kestää – lasts, takes (time)
neljäkymmentä – forty (literally four-ten)
minuuttia – minutes (grammatically the partitive singular form of minuutti, used after numbers)

So the sentence literally means: “Lesson lasts forty minutes”, which in natural English is “The lesson lasts forty minutes.”

Why is it minuuttia and not minuutit when it means “minutes”?

In Finnish, after a cardinal number greater than 1, the noun is normally in the partitive singular, not in the plural.

So you get:

yksi minuutti – one minute (nominative singular)
kaksi minuuttia – two minutes (partitive singular)
viisi minuuttia – five minutes (partitive singular)
neljäkymmentä minuuttia – forty minutes (partitive singular)

Even though English uses a plural form (minutes), Finnish does not: it keeps the word in singular but in the partitive case (minuuttia).

How is neljäkymmentä formed, and why is “40” one long word?

Finnish writes many numbers as one word, especially the tens, hundreds, etc.

neljä – four
kymmenen – ten
kymmentä – partitive form of kymmenen, used in compounds for tens

For 40, Finnish combines:

neljä
- kymmentä → neljäkymmentä (four-ten)

Other examples:

kaksikymmentä – 20 (two-ten)
kolmekymmentä – 30 (three-ten)
viisikymmentä – 50 (five-ten)

To add units after the tens, you add another word:

neljäkymmentäviisi minuuttia – 45 minutes (literally four-ten-five minutes)

So neljäkymmentä must be written as a single word.

Why is there no word for “the” in Oppitunti kestää neljäkymmentä minuuttia?

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

The bare noun oppitunti can correspond to:

a lesson
the lesson
or just lesson in a general sense

The context decides which English article you should use in translation. Here, in normal context (e.g. in a school schedule), English naturally chooses “The lesson lasts forty minutes.” even though Finnish just says Oppitunti with no article.

Why do we use kestää instead of the verb olla (“to be”) here?

Finnish uses kestää when talking about how long something lasts / how long it takes.

Oppitunti kestää neljäkymmentä minuuttia.
– The lesson lasts forty minutes.

The verb olla (“to be”) is not used for duration in this way. You would not say:

✗ Oppitunti on neljäkymmentä minuuttia.

That sounds wrong or at least very unnatural for duration.

Some related patterns:

Matka kestää tunnin. – The trip lasts an hour.
Elokuva kestää kaksi tuntia. – The movie lasts two hours.

Note that kestää can also mean to endure / to stand (e.g. En kestä tätä. – I can’t stand this.), but here it clearly means to last / to take time.

What exactly does oppitunti mean, and how is it different from tunti alone?

tunti by itself means hour, and also often class period in a school context.
oppitunti specifically means a lesson, class session (an hour or period of teaching/learning).

You might see both, depending on the style and context:

Tunti kestää neljäkymmentäviisi minuuttia.
– The (class) hour lasts 45 minutes.
Oppitunti alkaa kello yhdeksän.
– The lesson starts at nine o’clock.

In ordinary school language, oppitunti emphasizes that it’s a teaching/learning period, not just 60 minutes of time.

Can the word order change, or must it be Oppitunti kestää neljäkymmentä minuuttia?

The basic and most neutral order is:

Oppitunti kestää neljäkymmentä minuuttia.

But Finnish word order is somewhat flexible, especially for emphasis. For example:

Neljäkymmentä minuuttia oppitunti kestää.
– Roughly: It’s forty minutes that the lesson lasts. (emphasizing the duration)

This version is more marked and not the default, but it’s grammatically correct.

You would generally stick with the original order unless you have a specific reason (like contrast or emphasis) to change it.

How is kestää conjugated, and why does it end with -ää here?

The base form is kestää. In the present tense:

minä kestän – I last / I endure
sinä kestät – you last / you endure
hän kestää – he/she/it lasts
me kestämme – we last
te kestätte – you (pl.) last
he kestävät – they last

In Oppitunti kestää…, the subject oppitunti is third person singular, so the verb also takes the third person singular form: kestää.

The -ää is part of the verb’s stem and is kept in this form (similar to English last staying the same with it: it lasts).

Why is minuuttia in the partitive case? What does the partitive express here?

The partitive case (minuuttia) is required after cardinal numbers larger than 1. In this construction, the partitive is not expressing incompleteness or “some of” in the usual sense; instead, it’s simply the standard grammatical pattern for counted items:

kaksi kirjaa – two books
kolme lasta – three children
viisi omenaa – five apples
neljäkymmentä minuuttia – forty minutes

All these nouns (kirjaa, lasta, omenaa, minuuttia) are partitive singular. Here the partitive is triggered by the number and is just a fixed rule of Finnish grammar.

How would I say other durations, like 45 minutes or 1 hour, using the same pattern?

Use the same structure: [subject] + kestää + [number] + [time word in partitive singular].

Examples:

Oppitunti kestää kolmekymmentä minuuttia.
– The lesson lasts thirty minutes.
Oppitunti kestää neljäkymmentäviisi minuuttia.
– The lesson lasts forty‑five minutes.
Oppitunti kestää tunnin.
– The lesson lasts an hour.
(Here tunnin is the genitive of tunti; with “one hour” you often use tunnin rather than yksi tunti in this type of sentence.)
Oppitunti kestää puolitoista tuntia.
– The lesson lasts one and a half hours.

So for many minutes you use the number + minuuttia; for a single hour in this pattern you typically say tunnin.

How is Oppitunti kestää neljäkymmentä minuuttia pronounced, especially ä and long vowels?

Key points:

Stress is always on the first syllable of each word:
OP-pi-tun-ti KES-tää NEL-jä-kym-men-tä MI-nuut-tia
ä is pronounced like the a in English “cat”, not like a in “father”.
- oppitunti – op-pi-tun-ti (the u is like oo in book)
- kestää – kes-tää (the ää is a long ä, held about twice as long)
- neljäkymmentä – nel-jä-kym-men-tä
Long vowels are written with double letters and must be held longer:
- kestää – ää is long
- minuuttia – uu is long

Approximate IPA (simplified):
[ˈopːiˌtunti ˈkestæː ˈneljækymˌmentæ ˈminuːtːiɑ]

Getting the length of vowels and consonants right is important in Finnish, because it can change meanings.