Puhumme tästä aiheesta usein, koska se on tärkeä sekä lapsille että aikuisille.

Finnish usually does not need separate subject pronouns, because the verb ending already shows the person.

• puhua = to speak / to talk
• puhu-mme = we speak / we talk

The ending -mme means “we” (1st person plural). So puhumme on its own already means “we speak / we talk”.

You can add me (we) for emphasis or contrast:

• Me puhumme tästä aiheesta usein, mutta he eivät.
  We talk about this topic often, but they don’t.

In neutral sentences, it is normal and more natural to leave me out and just say Puhumme.

Puhumme comes from the basic form puhua (to speak / to talk).

Conjugation (present tense, indicative):

• minä puhun – I speak
• sinä puhut – you (sg) speak
• hän puhuu – he / she speaks
• me puhumme – we speak
• te puhutte – you (pl) speak
• he puhuvat – they speak

So:

• Stem: puhu-
• Ending: -mme (we)

puhu- + -mme → puhumme = we speak / we talk.

The phrase puhua jostakin (to talk about something) requires the elative case (the “from / out of” case).

• tämä → tästä = “from this / about this”
• aihe → aiheesta = “about the topic” / “about the subject”

Putting them together:

• tästä aiheesta = about this topic

Both tästä and aiheesta are in the elative case, and tästä works like a demonstrative determiner (“this”) modifying aiheesta. This is very normal in Finnish:

• tässä talossa = in this house
• tästä kirjasta = from/about this book
• tästä aiheesta = about this topic

Both tästä and aiheesta are in the elative case (ending -sta / -stä).

• tämä (this) → tästä (from this / about this)
• aihe (topic, subject) → aiheesta (from the topic / about the topic)

With the verb puhua, the thing you talk about is normally in the elative:

• puhua jostakin = to talk about something
  
  • Puhumme säästä. – We talk about the weather.
  • Puhun sinusta. – I talk about you.

So tästä aiheesta literally is “from this topic”, but idiomatically it means “about this topic”.

Yes. Both are correct and natural:

• Puhumme tästä aiheesta usein.
• Puhumme usein tästä aiheesta.

Word order in Finnish is quite flexible. Both versions mean “We talk about this topic often.”

The small nuance:

• Puhumme tästä aiheesta usein slightly emphasizes the topic (this topic is something we often talk about).
• Puhumme usein tästä aiheesta slightly emphasizes the frequency (often) in relation to that topic.

In everyday speech, they are very close in meaning; both are fine.

koska is a subordinating conjunction meaning “because”.

In the sentence:

• ..., koska se on tärkeä sekä lapsille että aikuisille.
  = ..., because it is important for both children and adults.

You can reverse the clause order:

• Koska se on tärkeä sekä lapsille että aikuisille, puhumme tästä aiheesta usein.
  = Because it is important for both children and adults, we talk about this topic often.

This is normal Finnish. The meaning stays the same; the difference is which part you present first for emphasis or flow.

Here se = “it”, referring to the topic (aihe) or this topic (tämä aihe / tämä aihealue).

• Koska se on tärkeä...
  = Because it is important...

You would not use hän here. hän is used for people (he/she) or personified things, not for a neutral “it” like a topic.

So:

• se → it (things, animals, abstract ideas, etc.)
• hän → he / she (a person, or personified entity)

In this sentence, se is the normal and only natural choice.

Both se on tärkeä and se on tärkeää can be grammatically correct, but they have slightly different nuances.

In the given sentence:

• se on tärkeä uses tärkeä (nominative singular), agreeing with se (it).
  This sounds more definite and concrete:
  → It is important (as a clear, stated fact about this specific thing).

se on tärkeää uses tärkeää (partitive singular). This may sound:

• more general / abstract (it is of importance), or
• like you are describing importance in a more vague or “mass-like” way.

In everyday usage:

• se on tärkeä = straightforward “it is important” about a specific, countable thing (this topic).
• se on tärkeää = often more general (e.g. Oppiminen on tärkeää. – Learning is important.)

Here, se on tärkeä fits very well because you’re talking about this specific topic being important.

sekä ... että ... is a correlative pair meaning roughly “both ... and ...”.

• sekä lapsille että aikuisille
  = for both children and adults

Comparison:

• lapsille ja aikuisille = for children and adults
• sekä lapsille että aikuisille = for both children and adults (slightly more balanced or emphasized)

Often you could use ja or sekä ... että ... with little difference, but sekä ... että ...:

• sounds a bit more formal or emphatic, and
• highlights that both parts are equally included.

Both lapsille and aikuisille are in the allative case (ending -lle), plural form.

Base forms:

• lapsi = child
• aikuinen = adult

Allative plural:

• lapsi → lapsille (to/for children)
• aikuinen → stem aikuis- → aikuisille (to/for adults)

The allative often expresses:

• direction to someone (antaa lapsille = give to children), or
• “for” someone in a beneficiary sense.

In this sentence:

• tärkeä lapsille = important for children
• tärkeä aikuisille = important for adults

So sekä lapsille että aikuisille = for both children and adults.

Yes, in standard written Finnish, you normally put a comma before koska when it starts a subordinate clause:

• Puhumme tästä aiheesta usein, koska se on tärkeä...
• En tule, koska olen sairas.

Similarly, if the koska-clause comes first, it is followed by a comma:

• Koska se on tärkeä sekä lapsille että aikuisille, puhumme tästä aiheesta usein.

So in both orders, there is a comma separating the main and subordinate clause.

You cannot simply replace usein with paljon here without changing the meaning or making it odd.

• usein = often, frequently (talks about frequency)

  • Puhumme tästä aiheesta usein. = We talk about this topic often.

• paljon = a lot, much, many (talks about amount / quantity)

  • Puhumme tästä aiheesta paljon. = We talk a lot about this topic.

Both sentences are correct Finnish, but they mean slightly different things:

• usein → how frequently you talk about it.
• paljon → how much you talk about it (amount / extent of talking).

So you can use paljon, but that is a different (though related) idea, not a direct synonym for usein.