Learn Hardcore Finnish: Kävelen usein samaa korttelia ympäri, kun puhun puhelimessa suomeksi. - I often walk around the same block when I speak on the phone in Finnish.

So Kävelen usein… already means “I often walk…”.
You can say Minä kävelen usein…, but that adds emphasis to I, like “I (as opposed to someone else) often walk…”. In a neutral sentence, the pronoun is left out.

Why is samaa korttelia in the partitive case and not sama kortteli?

Kortteli means roughly a city block. In the sentence, we have:

samaa = partitive singular of sama (the same)
korttelia = partitive singular of kortteli

So samaa korttelia is in the partitive.

Reasons:

Movement around something in a repetitive or unbounded way often uses the partitive:
- Kävelen puistoa ympäri. – I walk around the park (not just once from point A to B, but more generally / repeatedly).
- Juoksen taloa ympäri. – I run around the house.
The idea is that you’re not “completing” the object in a single, bounded action; the motion is ongoing or repeated. That often triggers the partitive.
The adjective must agree in case with the noun:
- nominative: sama kortteli
- partitive: samaa korttelia

So samaa korttelia is used because korttelia is partitive due to this “moving around an area” meaning, and samaa agrees with it.

What exactly does kortteli mean? Is it like “block” in English?

Yes, it’s very close to English “(city) block.”

kortteli = a block of buildings surrounded by streets, typically in a city.
It’s the unit you use when you say things like “three blocks away”:
- Kolmen korttelin päässä. – Three blocks away.

So samaa korttelia ympäri is literally “around the same block,” just like in English.

What does ympäri mean here, and how is it different from ympärillä and ympärille?

All three relate to “around,” but they differ in grammar and nuance.

ympäri (adverb/postposition with partitive)
- Used with movement or spread around something:
  - Kävelen samaa korttelia ympäri. – I walk around the same block.
  - Lentolehtisiä on ympäri kaupunkia. – There are flyers all around the city.
- Typically takes a partitive noun: puistoa ympäri, talvea ympäri, etc.
ympärillä (adessive form, more static “around”)
- Describes location around something, usually more static:
  - Istuimme pöydän ympärillä. – We sat around the table.
- Emphasis is on where people/things are, not on movement around.
ympärille (allative form, movement to around something)
- Movement into a position around something:
  - Keräännyimme nuotion ympärille. – We gathered around the campfire.
- Focus is on moving from elsewhere to the surrounding area.

In your sentence, you have continuous movement around something, so ympäri + partitive is the natural choice: samaa korttelia ympäri.

Could the word order be Kävelen usein ympäri samaa korttelia instead of Kävelen usein samaa korttelia ympäri?

Yes, that word order is also possible and grammatical:

Kävelen usein samaa korttelia ympäri.
Kävelen usein ympäri samaa korttelia.

Both mean the same thing: you often walk around the same block.

Nuance:

samaa korttelia ympäri is probably a bit more common and flows very naturally.
ympäri samaa korttelia sounds slightly more “spelled out” or emphatic about the “around” part, but it’s still perfectly natural.

In Finnish, adverbs/postpositions like ympäri can appear either before or after the noun phrase, especially in spoken language. Both orders here are fine.

What is the role of usein here, and where can it go in the sentence?

Usein means “often” and is an adverb of frequency.

Common placements:

Kävelen usein samaa korttelia ympäri…
Usein kävelen samaa korttelia ympäri…

Both are correct. The differences:

Kävelen usein… is the most neutral everyday order.
Usein kävelen… slightly emphasizes often, like “I often walk…” (as opposed to seldom/rarely).

You could theoretically move usein around more, but some positions start to sound unnatural. These two are the most idiomatic in this sentence.

Why is it puhun puhelimessa and not puhun puhelimella?

This is largely idiomatic.

puhua puhelimessa (literally: “to speak in the phone”)
- Means “to be talking on the phone” (having a phone conversation).
- This is the normal expression for “I’m on the phone.”
puhua puhelimella
- Would be interpreted more like “speak with/by means of the phone.”
- This sounds unusual; you don’t normally say it this way.

Related useful patterns:

soittaa puhelimella – to call with a phone (phone as instrument).
puhua puhelimeen – to speak into the phone (direction towards the device, e.g. “Speak into the phone so I can hear you”).

So in standard everyday Finnish, puhun puhelimessa is the correct way to say “I speak on the phone / I’m on the phone.”

Why is it suomeksi and not suomea or just suomi?

All of these forms exist, but they’re used differently.

suomeksi (translative case, -ksi)
- Typical structure: puhua + language + -ksi
- Means “in (a language)” in the sense of the language of the current conversation:
  - Puhun puhelimessa suomeksi. – I speak in Finnish on the phone.
suomea (partitive)
- puhua suomea means “to speak Finnish (as a language)”, often about skill or general ability:
  - Puhun suomea. – I speak Finnish (I know the language).
- You can say Puhun puhelimessa suomea, and it’s grammatically fine, but it focuses a bit more on the language as an object (“I speak (some) Finnish on the phone”).
suomi (nominative)
- Just the name of the language: Suomi = Finnish.
- Not used directly after puhua in this meaning.

In your sentence, suomeksi is very natural because you’re describing the language of this particular phone conversation: “when I talk on the phone in Finnish.”

What does kun do here, and how is it different from koska?

In this sentence, kun introduces a subordinate clause of time:

kun puhun puhelimessa suomeksi = “when I speak on the phone in Finnish” / “whenever I’m speaking on the phone in Finnish.”

kun can mean:

when (time):
- Kun tulen kotiin, syön. – When I get home, I eat.
In spoken Finnish, sometimes also because / since, but here the main reading is temporal (when).

koska is more strictly “because”:

Kävelen samaa korttelia ympäri, koska puhun puhelimessa suomeksi.
= I walk around the same block because I’m talking on the phone in Finnish.

That would make your walking a consequence of speaking Finnish.
With kun, the idea is mainly simultaneity: these two things happen at the same time (and often, repeatedly).

Why is there a comma before kun in Finnish, when in English you might not put a comma before “when”?

Finnish punctuation rules are different from English here.

General rule in Finnish:

You always separate a main clause and a subordinate clause with a comma, regardless of the word order.

So:

Kävelen usein samaa korttelia ympäri, kun puhun puhelimessa suomeksi.
Kun puhun puhelimessa suomeksi, kävelen usein samaa korttelia ympäri.

Both must have a comma between the two clauses in standard written Finnish, even though in English you might write:

I often walk around the same block when I speak on the phone in Finnish. (often without a comma)

Why are both verbs in the present tense? Could you use the past tense?

Both verbs are in the Finnish present tense:

Kävelen – I walk / I am walking
puhun – I speak / I am speaking

Finnish present tense covers both English “simple present” and “present continuous.” Here it expresses a habitual action:

Kävelen usein… kun puhun…
≈ “I often walk… when I speak / whenever I’m speaking…”

To talk about a past habit, you would put both clauses in the past:

Kävelin usein samaa korttelia ympäri, kun puhuin puhelimessa suomeksi.
= I often walked around the same block when I spoke / was speaking on the phone in Finnish.

Keeping the tenses aligned in the two clauses makes it clear they refer to the same time frame.

Could you replace kun puhun puhelimessa suomeksi with puhuessani puhelimessa suomeksi? What’s the difference?

Yes, you can. That uses a non-finite (infinitive) construction:

puhuessani = “while I am speaking” / “when I speak”
- from the 3rd infinitive puhuessa
  - possessive suffix -ni = “while my speaking”

So you could say:

Kävelen usein samaa korttelia ympäri puhuessani puhelimessa suomeksi.

Meaning-wise it’s very close: “I often walk around the same block while speaking on the phone in Finnish.”

Difference:

kun puhun… is more neutral and very common in everyday speech and writing.
puhuessani… is more compact and a bit more formal/literate. You see this style more in written Finnish (essays, books, formal texts) than in casual conversation.