Learn Hardcore Finnish: Kävelen metsän läpi.

So kävelen literally means I walk / I am walking.
Because Finnish verb endings already show the person, the subject pronoun minä (I) is usually left out unless you want to emphasize it:

Kävelen metsän läpi. = I walk through the forest.
Minä kävelen metsän läpi. = I walk through the forest (not someone else, or stronger emphasis on “I”).

Why is it metsän and not metsä? What case is this?

The base form is metsä (a forest). In the sentence it appears as metsän, which is the genitive singular form.

The postposition läpi (through) requires the noun before it to be in the genitive:

metsä → metsän läpi = through the forest
talo (house) → talon läpi = through the house
kaupunki (city) → kaupungin läpi = through the city

So metsän is there because läpi governs the genitive case.

What kind of word is läpi? Is it like a preposition?

Läpi is a postposition. It works like an English preposition (it shows a relationship like “through”), but it usually comes after the noun instead of before it.

Structure:

[noun in genitive] + läpi

Examples:

metsän läpi = through the forest
talon läpi = through the house
maan läpi = through the earth

So yes, it’s functionally similar to the English preposition through, but it appears after the noun phrase.

Is there a difference between “I walk” and “I am walking” in Finnish?

No. Finnish has only one present tense form for both.

Kävelen metsän läpi can mean:

I walk through the forest (habitual / general)
I am walking through the forest (right now / current action)

Context usually makes it clear which meaning is intended. If you need to be very explicit, you use adverbs or time expressions rather than a different tense:

Kävelen nyt metsän läpi. = I am walking through the forest now.
Kävelen usein metsän läpi. = I often walk through the forest.

How is ä pronounced in words like kävelen, metsän, and läpi?

Ä is a separate vowel from A in Finnish.

a is like the a in “father” (low, back vowel)
ä is closer to the a in “cat” (front, more open “eh/æ” sound)

So:

kävelen ≈ “kae-veh-len” (all short vowels)
metsän ≈ “mets-æn” (like “mets-aen” with short vowels)
läpi ≈ “læ-pi” (short “æ” + short “i”)

The length (short vs long) and the exact quality matter in Finnish; a and ä are different letters and can change meaning.

Could I change the word order to “Metsän läpi kävelen”? Does it mean the same thing?

Yes, you can say Metsän läpi kävelen, and it is grammatically correct. The basic meaning is still “I walk through the forest,” but the emphasis changes.

Kävelen metsän läpi.
– Neutral word order; focus on the action “I walk.”
Metsän läpi kävelen.
– Slightly more emphasis on metsän läpi (through the forest), for example to contrast with some other route:
- Metsän läpi kävelen, en tien viertä.
  I walk through the forest, not along the road.

Finnish word order is relatively flexible, and changes often express nuances of emphasis or contrast rather than grammatical roles.

What is the difference between metsän läpi and metsässä?

They express different spatial relations:

metsän läpi = through the forest
- You start outside the forest, go inside, and come out the other side. It emphasizes movement across the forest from one side to another.
metsässä = in the forest / in a forest
- You are (or move) inside the forest area, but it doesn’t say anything about entering or leaving it.

Example:

Kävelen metsän läpi.
I walk through the forest (from one side to the other).
Kävelen metsässä.
I walk in the forest (I am walking inside the forest, not necessarily crossing it).

Do Finns ever use a word like “the” before metsän? How do you know if it is “a forest” or “the forest”?

Finnish has no articles like “a/an” or “the”.

Metsän could be understood as:

through a forest
through the forest

The exact interpretation depends on context:

If you were just describing your route in general:
Kävelen usein metsän läpi. = I often walk through a forest.
If both speakers already know which specific forest is meant:
In that context, metsän will naturally be understood as the forest.

The language relies on shared context, word order, and sometimes demonstratives (tämän, sen, etc.) rather than articles.

Why doesn’t the sentence use the partitive case? I thought movement often uses the partitive.

Movement can trigger the partitive in many situations, but not always. In this pattern:

[genitive] + läpi

the case is determined by läpi, which always takes a genitive complement, regardless of movement:

metsän läpi
talon läpi
puiston läpi

The partitive appears in different kinds of movement expressions, such as:

Juoksen metsää pitkin. = I run along the forest.
Juoksen metsään. = I run into the forest.
Juoksen metsässä. = I run in the forest.

But with läpi, you specifically use the genitive.

Are there other ways to say “through” besides läpi? Are they different?

Yes, Finnish has several words that can translate as “through”, but they have slightly different nuances:

läpi – through, across (literally passing inside and out the other side)
- Kävelen metsän läpi. = I walk through the forest.
kautta – via, by way of (often more about route than literal “inside”)
- Kävelen puiston kautta kotiin. = I walk home through / via the park.
poikki – across (often cutting a line or area across its width)
- Kävelen pellon poikki. = I walk across the field.
halki – through, across (similar to läpi, often a bit more literary/formal)
- Kävelen metsän halki. = I walk through the forest.

All of these behave like postpositions and typically take the genitive: metsän kautta, pellon poikki, metsän halki, etc.

How would I say this sentence in the negative?

To negate Kävelen metsän läpi, you use the negative verb en and the connegative form of the main verb:

En kävele metsän läpi.
= I don’t walk through the forest / I am not walking through the forest.

Structure:

en = I do not (1st person singular of the negative verb)
kävele = stem form used with negation (no -n)
metsän läpi stays the same (the negation affects the verb, not the cases of the nouns)

How would this sentence look in the past tense: “I walked through the forest”?

You use the imperfect (simple past) of kävellä:

Kävelin metsän läpi. = I walked through the forest.

Comparison:

Kävelen metsän läpi. = I walk / I am walking through the forest.
Kävelin metsän läpi. = I walked through the forest.

The noun phrase metsän läpi stays the same; only the verb changes tense:

kävelen → kävelin (1st person singular past).