Tämä osa kirjasta on kiinnostava.

This part of the book is interesting.

Breakdown of Tämä osa kirjasta on kiinnostava.

• olla: to be
• tämä: this
• kirja: the book
• kiinnostava: interesting
• osa: the part

Questions & Answers about Tämä osa kirjasta on kiinnostava.

Why is it osa kirjasta and not something like osa kirjaa or kirjan osa for “part of the book”?

Finnish has several ways to say “part of X,” and they’re not all identical:

• osa kirjasta

  • kirjasta is in the elative case (-sta = “from, out of”).
  • Pattern: osa + elative is a very common way to say “a part of / a section from (some larger whole).”
  • It often feels neutral and can hint at “one of the parts taken from the book.”

• kirjan osa

  • kirjan is in the genitive case (“the book’s part”).
  • Literally: “the book’s part.”
  • Used more like a structural or conceptual part that belongs to the book as an object or whole (e.g. Part I of the book, an official section).

• osa kirjaa

  • kirjaa is partitive.
  • This could appear e.g. in some quantifying contexts (like “I read part of the book”: luin osan kirjaa), but by itself osa kirjaa is less natural as a standalone noun phrase than osa kirjasta when you just mean “a section of the book.”

In your sentence, osa kirjasta is the most natural way to express “this part of the book (that we’re talking about now).”

What case is kirjasta, and why is that case used here?

Kirjasta is in the elative singular:

• Stem: kirja (book)
• Elative ending: -sta (or -stä with front vowels)
• kirja → kirjasta = “from (the) book” / “out of (the) book”

In constructions like osa + elative, the elative is used to mark the larger whole from which a smaller part comes:

• osa kirjasta = “a part from the book” → “a part of the book”
• pala kakusta = “a piece (from) the cake” → “a piece of the cake”

So the elative is the natural case to show that osa is a portion taken out of the book.

Why is it Tämä and not Tämän at the beginning?

Tämä is the nominative form of the demonstrative pronoun meaning “this”:

• Nominative: tämä (used for subjects and basic citation form)
• Genitive: tämän
• Partitive: tätä

In your sentence:

• Tämä osa kirjasta is the subject of the sentence.
• Subjects normally appear in the nominative case, so we use tämä, not tämän.

If you changed the structure, you might see tämän, e.g.:

• Pidän tämän osan kirjasta eniten.
  “I like this part of the book the most.”
  Here tämän osan is in the genitive (tämän) + accusative/genitive (osan) as the object.

Can I also say Tämä kirjan osa on kiinnostava? Does it mean the same thing?

You can say Tämä kirjan osa on kiinnostava, and it is grammatical, but the nuance shifts slightly:

• Tämä osa kirjasta on kiinnostava.
  Focuses on a part taken from the book, often understood as some particular section or excerpt.
  The structure osa kirjasta is very idiomatic for “part of the book.”

• Tämä kirjan osa on kiinnostava.
  Feels more like “this part of the book (as a structural unit that belongs to the book itself).”
  That is, more like “this section/chapter of the book” as an integral, labelled part (e.g. Chapter 2, Part III).

In many everyday contexts they overlap and both are understandable, but osa kirjasta is the more typical phrase when just informally saying “this part of the book is interesting.”

Why is kiinnostava in that exact form? Why not kiinnostavaa?

Kiinnostava here is in the nominative singular, because it’s a predicative adjective agreeing with the subject:

• Subject: Tämä osa kirjasta (singular)
• Copula verb: on (“is”)
• Predicative: kiinnostava (nominative, singular, matching the subject)

Pattern:

• Tämä kirja on hyvä. – “This book is good.”
• Nuo elokuvat ovat tylsiä. – “Those movies are boring.” (plural, so tylsiä / partitive plural)

You would use kiinnostavaa (partitive) in sentences where the predicative is in partitive for aspect or quantity reasons, for example:

• Kirja on kiinnostavaa luettavaa.
  “The book is interesting reading.” (Here kiinnostavaa luettavaa is a kind of mass-like complement.)

But in your simple classification sentence “X is interesting,” nominative kiinnostava is the normal choice.

Is kiinnostava an adjective or a verb form?

It is both in origin, but functions as an adjective in this sentence.

• Verb: kiinnostaa = “to interest”
• Its present active participle: kiinnostava = “interesting (one/thing)”
  Literally “one that interests.”

Finnish often uses the present active participle of a verb as an adjective describing a quality:

• kiinnostava kirja – “an interesting book” (“a book that interests [someone]”)
• väsyttävä päivä – “a tiring day” (“a day that tires [you]”)

So grammatically, kiinnostava is a participle form of kiinnostaa, but in practice learners can safely treat it like a regular adjective meaning “interesting.”

What’s the difference between kiinnostava and kiinnostunut?

They correspond roughly to English interesting vs interested:

• kiinnostava = “interesting” (causing interest)

  • Tämä osa kirjasta on kiinnostava.
    “This part of the book is interesting.”

• kiinnostunut = “interested” (having interest)

  • Olen kiinnostunut tästä osasta kirjasta.
    “I am interested in this part of the book.”

So:

• Use kiinnostava to describe things that attract interest.
• Use kiinnostunut to describe people (or sometimes animals etc.) who feel interest.

Why is the verb on and not something like olla or a form that changes with the subject?

On is the 3rd-person singular present tense of the verb olla (“to be”):

• infinitive: olla – “to be”
• 1st sg: olen – “I am”
• 2nd sg: olet – “you are”
• 3rd sg: on – “he/she/it is” or “there is”
• etc.

In your sentence, the subject Tämä osa kirjasta is 3rd person singular, so the correct present tense form is on:

• Tämä osa kirjasta on kiinnostava.
  “This part of the book is interesting.”

Finnish does conjugate verbs according to person and number, but on happens to be the form used with any 3rd-person singular subject (he, she, it, this, that, the book, the part, etc.).

Could I change the word order, like Kirjasta tämä osa on kiinnostava? Is that correct?

Yes, that word order is grammatically correct, but it sounds more marked and emphasizes different things.

• Neutral, most common:

  • Tämä osa kirjasta on kiinnostava.

• Emphatic or contrastive:

  • Kirjasta tämä osa on kiinnostava.
    Roughly: “Of the book, this part is interesting (implying other parts maybe aren’t).”

Finnish word order is relatively flexible. Moving kirjasta to the front adds emphasis or contrast, while Tämä osa kirjasta on kiinnostava is the default neutral way to say it.

How do I know that Tämä osa kirjasta is the subject and kiinnostava is the description?

Several clues:

1. Position & structure
   The phrase Tämä osa kirjasta comes before the verb on, which is a common subject position in neutral Finnish sentences.

2. Case

   • Tämä osa kirjasta is in nominative (tämä, osa) + a complement (kirjasta).
   • Predicative adjectives that describe the subject also appear in the nominative when the subject is a countable, definite thing.

3. Meaning pattern
   The structure [Noun phrase] + on + [adjective (nominative)] is the standard pattern for “X is Y”:

   • Talo on iso. – “The house is big.”
   • Kirja on pitkä. – “The book is long.”
   • Tämä osa kirjasta on kiinnostava. – “This part of the book is interesting.”

Finnish has no articles like “the” or “a”. Is Tämä kind of replacing “the” here?

Tämä (“this”) is not an article, but a demonstrative pronoun, similar to English “this” / “that.”

Because Finnish has no articles, demonstratives often carry some of the clarity that English articles give:

• kirja = could be “a book” or “the book,” depending on context.
• tämä kirja = explicitly “this book.”
• tämä osa kirjasta = “this part of the book.”

So tämä doesn’t replace “the” directly; instead, it specifically points to something near in context (physically, or in the conversation), like English “this.” The definiteness (“the part”) in your translation comes partly from tämä and partly from context.

Can I drop osa and say Tämä kirjasta on kiinnostava?

No, Tämä kirjasta on kiinnostava is not grammatical in standard Finnish.

• Kirjasta (elative case) means “from the book / out of the book,” but without osa (or some other head noun), it doesn’t stand as a clear noun phrase. It’s more like a loose adverbial (“from the book”) than a subject.

You need a head noun like osa (“part”), kohta (“passage, point”), luku (“chapter”), etc.:

• Tämä osa kirjasta on kiinnostava.
• Tämä kohta kirjasta on kiinnostava.
• Tämä luku kirjasta on kiinnostava.

All of these are fine; just removing osa leaves the sentence without a proper subject.

How is Tämä osa kirjasta on kiinnostava pronounced? Where is the stress?

Key points:

1. Word stress
   In Finnish, the primary stress is always on the first syllable of each word:

   • TÄ-mä
   • O-sa
   • KIR-jas-ta
   • ON
   • KIIN-nos-ta-va (secondary stress normally appears on every second syllable, so here on kiin and a weaker one often on ta)

2. Vowel length
   Double vowels are long:

   • Tämä – short vowels.
   • kiinnostava – ii is long: kii- (held slightly longer).

3. Consonant length
   Double consonants (not in this sentence) would be long; here you just have regular single consonants.

4. Rhythm
   Finnish has a relatively even, syllable-based rhythm: each syllable gets roughly equal time, with a clear strong first syllable in each word:

   • TÄ-mä O-sa KIR-jas-ta ON KIIN-nos-ta-va.

This gives a steady, “machine-gun” rhythm compared to English’s more variable stress pattern.