Learn Hardcore Finnish: Katson saman ohjevideon monta kertaa, jolloin uudet sanat jäävät paremmin mieleen. - I watch the same tutorial video many times, which is when the new words stick in my mind better.

Sama means the same. In this sentence it’s in the genitive singular form saman because it has to agree with the noun ohjevideon, which is also in the genitive singular.

Finnish determiners/adjectives usually match the noun in case and number:

nominative: sama ohjevideo – the same tutorial video
genitive: saman ohjevideon – of the same tutorial video / the same tutorial video (as a total object)

So saman ohjevideon literally is the same tutorial video in the genitive case, used here as the total object of the verb katson.

Why is ohjevideon in the form with -n at the end?

Ohjevideon is the genitive singular of ohjevideo (tutorial video).

In Finnish, the direct object of a verb like katsoa (to watch) can appear:

in genitive form for a total object (a complete, bounded event)
in partitive for an unbounded or incomplete event, or for some other grammatical reasons

Here, katson saman ohjevideon monta kertaa suggests you watch the entire video each time. That’s why ohjevideo appears as ohjevideon (genitive total object).

Compare:

Katson saman ohjevideon. – I watch the same tutorial video (through).
Katson samaa ohjevideota. – I am watching the same tutorial video (not necessarily to the end; ongoing or partial).

Could I also say “Katson samaa ohjevideota monta kertaa”? What’s the difference?

Yes, that sentence is grammatically correct:

Katson samaa ohjevideota monta kertaa.

Here both samaa and ohjevideota are partitive singular.

Nuance:

Katson saman ohjevideon monta kertaa
– focuses on complete viewings of the whole video, repeated many times.
Katson samaa ohjevideota monta kertaa
– focuses more on the activity of watching; grammatically more “open‑ended” or unbounded. It doesn’t strongly imply you always finish it.

In everyday speech, the difference is quite subtle, and both are often understood almost the same way, but the genitive version highlights the idea of repeated complete watchings a bit more.

What exactly is going on in monta kertaa? What case is kertaa?

Monta kertaa means many times.

monta is the partitive singular of moni (many).
kertaa is the partitive singular of kerta (time, occasion).

Numbers and some quantifying words (like monta) normally take the noun they count in the partitive singular:

kaksi kertaa – two times
kolme kertaa – three times
monta kertaa – many times

An alternative is monia kertoja (many times), where both words are in partitive plural. Monta kertaa is more common and idiomatic in this expression.

What does jolloin mean, and how does it work?

Jolloin is a relative adverb that literally means something like at which time / when, and often carries a consequential or result meaning close to and as a result / and then.

It links the main clause to a subordinate clause that describes what happens then / in that situation:

Katson saman ohjevideon monta kertaa, jolloin uudet sanat jäävät paremmin mieleen.
→ I watch the same tutorial video many times, whereupon / and then / and as a result the new words stick better in my memory.

You can think of jolloin as combining “when” + “so that / and then” into one word.

Why is there a comma before jolloin?

In Finnish, you usually put a comma before a subordinate clause introduced by words like jolloin, jotta, että, koska, kun, etc.

So:

main clause: Katson saman ohjevideon monta kertaa
subordinate clause: jolloin uudet sanat jäävät paremmin mieleen

They are separated by a comma:
Katson saman ohjevideon monta kertaa, jolloin uudet sanat jäävät paremmin mieleen.

Could I use something else instead of jolloin, like jotta or joten? Would it change the meaning?

You could, but there are nuances:

jolloin – when / and then / whereupon (time + result, relatively neutral)
joten – so / therefore (explicit logical consequence)
jotta – so that / in order that (purpose)

Possible alternatives:

Katson saman ohjevideon monta kertaa, joten uudet sanat jäävät paremmin mieleen.
→ stresses logical consequence: therefore the new words stick better.
Katson saman ohjevideon monta kertaa, jotta uudet sanat jäisivät paremmin mieleen.
→ expresses purpose: I watch it many times in order that the new words would stick better.
(note the usual conditional jäisivät after jotta)

The original with jolloin is slightly more neutral and descriptive: “in that situation, the result is that the words stick better.”

What does jäävät mieleen literally mean?

Literally, jäävät mieleen is:

jäävät – stay / remain (3rd person plural of jäädä)
mieleen – into the mind (allative form of mieli, mind)

So literally: “remain into the mind” → idiomatically: stick in one’s memory / mind.

It’s a common idiom:

Nimi ei jäänyt mieleen. – The name didn’t stick (in my mind).
Asia jäi hyvin mieleen. – The thing really stuck in my memory.

Why is jäävät plural here?

Because the subject of the clause is uudet sanat (new words), which is plural.

In Finnish, the verb usually agrees with the subject in number:

uusi sana jää mieleen – a new word sticks in (my) memory
uudet sanat jäävät mieleen – new words stick in (my) memory

So jäävät (3rd person plural) matches uudet sanat.

What form is mieleen, and why is that case used?

Mieleen is the allative singular of mieli (mind).

Allative (-lle / -lleen / -een depending on the stem) often expresses movement onto / toward / into something, or a more abstract “toward a mental state.”

In this idiom jäädä mieleen:

mieleen suggests to / into the mind
mielessä (inessive) would be in the mind

Compare:

Asia jäi mieleen. – The thing stuck in (came to) my memory.
Asia on mielessäni. – The thing is on my mind.

So mieleen is the standard form in the idiom jäädä mieleen.

Why is it paremmin and not parempi?

Parempi is the comparative adjective of hyvä (good), used with nouns:

parempi kirja – a better book
parempi muistaminen – better remembering

Paremmin is the comparative adverb of hyvin (well), used with verbs to say how something is done:

muistan paremmin – I remember better
sanat jäävät paremmin mieleen – the words stick in my mind better

In jäävät paremmin mieleen, paremmin modifies the verb jäävät (how they remain), so you need the adverb form.

What tense is katson, and how can it mean a habitual action?

Katson is the present tense (1st person singular) of katsoa.

In Finnish, the present tense covers:

actions happening right now
regular / habitual actions
general truths

So Katson saman ohjevideon monta kertaa most naturally means:

I (typically) watch the same tutorial video many times (habit / routine),

not just “I am watching it many times right now.” Context decides, and the presence of monta kertaa strongly suggests a habitual or repeated action.