Learn Hardcore Finnish: Tämä kanava julkaisee uuden ohjevideon joka maanantai, jolloin minulla on aikaa katsoa sen. - This channel publishes a new tutorial video every Monday, when I have time to watch it.

joka + [time word in nominative]
- joka päivä – every day
- joka viikko – every week
- joka kuukausi – every month
- joka maanantai – every Monday

You could also say jokainen maanantai, but that is less common and has a slightly more emphatic, “every single Monday” nuance. In normal speech, joka maanantai is the natural choice.

The noun (maanantai) stays in its basic form; joka takes care of the “every” idea and you don’t decline maanantai in this structure.

Why is it uuden ohjevideon and not uusi ohjevideo after julkaisee?

Julkaisee uuden ohjevideon means “publishes a new tutorial video”.

julkaisee – (he/she/it) publishes
uuden – new in the genitive singular (matching the noun)
ohjevideon – tutorial video in the genitive singular

The key point is the Finnish object case:

A complete, whole object (one full video that gets published) is usually in the genitive:
- julkaista uusi ohjevideo (dictionary form)
- → julkaisee uuden ohjevideon (in a real sentence, the object becomes genitive)

Because ohjevideo becomes ohjevideon (genitive), the adjective must agree in case:

uusi ohjevideo (basic form) → uuden ohjevideon (genitive object)

If the sentence talked about an indefinite or partial amount of videos, you’d use the partitive instead:

julkaisee ohjevideoita – publishes (some) tutorial videos (unspecified amount)

What exactly is ohjevideon? Is it a compound word, and why does only the end change?

Yes, ohjevideo is a compound word:

ohje = instruction, guidance
video = video
→ ohjevideo = instruction video / tutorial video

In Finnish compounds, only the last part of the compound takes the case ending:

basic form: ohjevideo
genitive singular: ohjevideon
- ohje stays the same
- video → videon

So we get uuden ohjevideon, not something like uuden ohjeenvideon.

Why is julkaisee in the present tense if this happens every Monday? Why not some special habitual form?

Finnish uses the simple present tense for:

things happening right now and
regular, repeated habits (like English “I go to the gym on Mondays”)

So:

Tämä kanava julkaisee uuden ohjevideon joka maanantai
= “This channel publishes a new tutorial video every Monday”
= “This channel puts out a new tutorial video every Monday”

There is no separate “habitual” tense in standard Finnish. The context (joka maanantai) makes it clear that this is a repeated, regular event.

What does jolloin mean here, and what does it refer back to?

Jolloin is a relative adverb of time, roughly meaning:

“at which time”, “when”

In this sentence:

joka maanantai, jolloin minulla on aikaa katsoa sen
= “every Monday, when I have time to watch it”

Jolloin refers back to the whole time phrase joka maanantai. You can think of it as:

joka maanantai, jolloin…
→ “every Monday, and on those Mondays I have time to watch it”

Compare:

kun minulla on aikaa – when I have time (a normal conjunction)
jolloin minulla on aikaa – when I have time (specifically on those Mondays; ties back to a time expression already mentioned)

Why is there a comma before jolloin?

In Finnish, you normally put a comma before a subordinate clause, including:

clauses introduced by että, koska, vaikka, kun, jolloin, etc.

So you write:

… joka maanantai, jolloin minulla on aikaa katsoa sen.

Because jolloin minulla on aikaa katsoa sen is a subordinate clause describing joka maanantai, Finnish punctuation requires the comma, even though in English you might not necessarily put a comma there.

Why is it minulla on aikaa instead of something like minä olen aikaa or minulla on aika?

Two separate things are going on:

Possession with the adessive case
Finnish usually expresses “having” with [person in adessive] + on:
- minulla on = I have (literally “on me is”)
- sinulla on = you have
- hänellä on = he/she has
So minulla on… = “I have …”
Aikaa in the partitive for “some time”
- aika = time (as a countable thing, or a specific time)
- aikaa = time in the partitive, used for an indefinite amount of time
Expressions like:
- minulla on aikaa – I have (some) time
- ei ole aikaa – I don’t have time

Putting it together:

minulla on aikaa
literally: “on me is time (some amount)”
idiomatically: “I have time”

Minä olen aikaa doesn’t work in Finnish; olla (“to be”) isn’t used that way for possession.

Why is aikaa in the partitive and not aika?

The partitive aikaa is used here because we are talking about an unspecified amount of time:

minulla on aikaa – I have (enough/some) time
onko sinulla aikaa? – do you have (any) time?

In Finnish, the partitive often expresses:

an incomplete or indefinite amount of something
something not fully bounded

Compare:

Minulla on aika huomenna kello kolme.
– I have an appointment / a specific time tomorrow at three.

vs.

Minulla on aikaa huomenna.
– I have (plenty of) time tomorrow.

In your sentence, we mean “I have time (to watch it)” in this general, indefinite sense, so aikaa (partitive) is the natural form.

Why is the verb katsoa in the basic infinitive form after minulla on aikaa?

Katsoa is in the first infinitive (dictionary form):

minulla on aikaa katsoa sen
= “I have time to watch it”

This is a common pattern:

minulla on aikaa + [verb in infinitive]
- minulla on aikaa lukea – I have time to read
- minulla on aikaa opiskella – I have time to study

So the structure is:

[someone in adessive] + on aikaa + [verb in infinitive]
expressing “someone has time to do something”.

You don’t conjugate the second verb (katsoa) here; you keep it in its infinitive form.

Why is it katsoa sen and not katsoa sitä?

Both sen and sitä mean “it”, but they differ in case and meaning:

sen – genitive / accusative (a total object)
sitä – partitive (a partial / ongoing object)

Here, katsoa sen expresses the idea of watching the whole video, completely:

“I have time to watch all of it.”

That’s why sen (total object, genitive/accusative) is used.

If the action were partial, ongoing, or not completed, Finnish would prefer sitä:

Minulla on aikaa katsoa sitä vähän.
– I have time to watch it a bit. (not necessarily all of it)

In your sentence, the natural assumption is that you’ll watch the entire video, so sen fits best.

What exactly does sen refer to, and why not repeat ohjevideon?

Sen is a pronoun that refers back to uuden ohjevideon:

uuden ohjevideon → that new tutorial video
sen → it (that video)

Repeating the full noun is possible but sounds heavy:

… jolloin minulla on aikaa katsoa sen uuden ohjevideon.
(grammatically possible, but clumsy here)

Instead, Finnish prefers a pronoun once the noun is clear from context. Sen is the genitive/accusative form of se, matching the object case.

Could the sentence be rephrased with kun instead of jolloin? What would change?

Yes, you could say:

Tämä kanava julkaisee uuden ohjevideon joka maanantai, kun minulla on aikaa katsoa sen.

Both are correct, but there is a nuance:

jolloin
- is a relative adverb
- directly ties the time of having time back to joka maanantai
- feels a bit more “on those Mondays when …”
kun
- is a more general subordinating conjunction (“when”)
- does not as strongly emphasize the direct link back to the specific phrase joka maanantai

In practice, both are fine; jolloin just sounds a bit more precisely anchored to that time expression mentioned right before it.