Learn Hardcore Finnish: Minun täytyy terottaa lyijykynän ennen sanakoetta. - I have to sharpen the pencil before the vocabulary test.

The person who “has to” do something is put in the genitive case (minä → minun), and täytyy stays in 3rd person singular regardless of who it is:

minun täytyy – I have to
sinun täytyy – you (sg.) have to
hänen täytyy – he/she has to
meidän täytyy – we have to
teidän täytyy – you (pl.) have to
heidän täytyy – they have to

“Minä täytyy” is ungrammatical in standard Finnish. The pattern with the genitive pronoun is the normal one.

Can I leave out “minun” and just say “Täytyy teroittaa lyijykynän ennen sanakoetta”?

You can, but the meaning becomes less specific:

Minun täytyy teroittaa lyijykynän…
→ I have to sharpen the pencil… (clearly “I”)
Täytyy teroittaa lyijykynän…
→ [Someone] has to sharpen the pencil… / One has to sharpen the pencil…

Leaving out minun is common in speech and informal writing when it’s obvious from context who the subject is. Grammatically it’s still the same täytyy + infinitive structure; the person is just understood but not said.

If you want to be clear for learners or in formal text, it’s better to keep minun.

What verb form is “terottaa” here, and why isn’t it conjugated (e.g. teroitan)?

In this sentence terottaa (standard: teroittaa, see next question) is in the 1st infinitive form, which is the basic dictionary form ending in -a/-ä.

With täytyy, you always use this infinitive form, not a personal form:

Minun täytyy teroittaa lyijykynä…
I have to sharpen the pencil…

Compare with:

Teroitan lyijykynän. – I sharpen the pencil. (here teroit- is conjugated for 1st person singular)

So the pattern is:

[Genitive pronoun] + täytyy + [infinitive]
Minun täytyy mennä, sinun täytyy opiskella, meidän täytyy lähteä, etc.

Is the spelling “terottaa” correct, or should it be “teroittaa”?

The standard dictionary form is teroittaa (with oi: t-e-r-o-i-t-t-a-a).

teroittaa lyijykynän – to sharpen a pencil

“Terottaa” is a common spelling mistake (you’ll see it, but it’s not considered standard). For correct written Finnish, use teroittaa.

So a standard version of the sentence would be:

Minun täytyy teroittaa lyijykynä ennen sanakoetta.

Why is it “lyijykynän” and not just “lyijykynä”?

Lyijykynän is the object of the verb “sharpen”, and in this sentence it is a total object.

For singular nouns, the total object usually looks like the genitive form (ending in -n):

nominative (basic form): lyijykynä – “pencil”
genitive / total object: lyijykynän – “(the) pencil” as a whole

We are talking about sharpening the whole pencil, a complete event, so the total object form is used:

Minun täytyy teroittaa lyijykynän.
→ I have to sharpen the pencil (completely).

Using bare lyijykynä here would be ungrammatical as an object.

When would I say “lyijykynää” instead of “lyijykynän”?

Lyijykynää is the partitive form. Partitive objects are used for, among other things:

Ongoing or incomplete actions
- Olen teroittamassa lyijykynää.
  I am (in the process of) sharpening the pencil.
Unspecified amount or “some of it”
(better examples with mass nouns: juon vettä – I drink (some) water)

In your sentence:

Minun täytyy teroittaa lyijykynän…
→ complete, goal-oriented action (get the pencil sharpened)

If you said:

Minun täytyy teroittaa lyijykynää…

it would sound more like you’re describing being engaged in sharpening a pencil, rather than the completion of the task. In most practical cases for a simple instruction like this, lyijykynän (total object) is the natural choice.

How would I explicitly say “my pencil” in this sentence?

To say “my pencil” you normally add a possessive suffix (and optionally keep the pronoun):

lyijykynäni = my pencil (nominative)
lyijykynäni / lyijykynäni → genitive is also lyijykynäni in form, but in context it functions as the total object.

So you could say:

Minun täytyy teroittaa lyijykynäni ennen sanakoetta.
→ I have to sharpen my pencil before the vocabulary test.

Often the minun is dropped because the suffix -ni already shows “my”:

Täytyy teroittaa lyijykynäni ennen sanakoetta.
→ I have to sharpen my pencil before the vocabulary test.

Your original lyijykynän without a suffix just means “the pencil” (or a contextually known pencil), not explicitly “my pencil”.

What form is “sanakoetta”, and why is it used after “ennen”?

The basic noun is sanakoe:

sana = word
koe = test, exam
→ sanakoe = vocabulary test / word test

Sanakoetta is the partitive singular of sanakoe.

The preposition/postposition ennen (“before”) always takes the partitive case:

ennen koulua – before school
ennen juhlia – before the party/parties
ennen sanakoetta – before the vocabulary test

So the pattern is:

ennen + [noun in partitive]

That’s why we say ennen sanakoetta, not ennen sanakoe or ennen sanakokeen.

Can I start the sentence with “Ennen sanakoetta”? Does the word order change the meaning?

Yes, you can change the word order:

Minun täytyy teroittaa lyijykynän ennen sanakoetta.
Ennen sanakoetta minun täytyy teroittaa lyijykynän.

Both are grammatically correct and mean the same thing: I have to sharpen the pencil before the vocabulary test.

The difference is mainly emphasis:

Original order is more neutral; it starts with who (minun) and what has to happen.
Starting with Ennen sanakoetta highlights the time frame: Before the vocab test, I have to…

Finnish word order is relatively flexible; core roles are mostly shown by case endings, not position.

What’s the difference between “täytyy”, “pitää”, and “on pakko” when they all can mean “have to / must”?

All three can express necessity, but with slightly different nuances and grammar.

täytyy (as in your sentence)
- Pattern: [genitive pronoun] + täytyy + infinitive
- Minun täytyy teroittaa lyijykynän.
- Neutral “have to / must”.
pitää
- Same type of pattern: Minun pitää teroittaa lyijykynän.
- Very common in speech, often interchangeable with täytyy.
- In some regions, pitää is more common than täytyy.
on pakko
- Pattern: [adessive pronoun] + on pakko + infinitive
  - Minulla on pakko teroittaa lyijykynä. (more naturally: Minun on pakko teroittaa lyijykynä.)
- Feels stronger, more like “I am forced to / I have no choice but to”.

For your sentence, the most natural versions are:

Minun täytyy teroittaa lyijykynä ennen sanakoetta.
Minun pitää teroittaa lyijykynä ennen sanakoetta.

“Minun on pakko teroittaa…” would suggest a very strong obligation.

Where are the equivalents of English “the” and “a” here? How do I know if it’s “a pencil” or “the pencil”?

Finnish has no articles (a/an, the). Definiteness and indefiniteness are expressed by:

Context
Word order
Case forms

In your sentence:

lyijykynän is the object form (genitive/total object). It can be understood as “the pencil” or “a pencil”, depending on context.
sanakoetta similarly is just “(a/the) vocabulary test.”

If the context is “I’m sitting in class right now, getting ready to write the test on my desk”, it will almost automatically be understood as “the pencil” and “the vocabulary test”.

If you really need to emphasize that it’s some random pencil, you’d usually add extra wording, not an article (e.g. jonkin lyijykynän – some pencil), but that’s much less common. Most of the time, Finnish simply doesn’t mark “a/the” at all.

How do you pronounce “lyijykynän”? It looks very difficult.

Syllables: lyi-jy-ky-nän
Main stress is always on the first syllable in Finnish: LYI-jy-ky-nän.

Rough guide for English speakers:

lyi – like “ly” in Lyon, with a very front ü sound ([y]): lips rounded as for oo but tongue as for ee. It’s two written vowels but felt as one sequence: lyi.
jy – again that front rounded vowel y; j is like English y in yes.
ky – k as in key, y again the same front rounded vowel.
nän – nä with ä like a in cat, but front; final n as normal.

IPA (approximate): [ˈlyi̯jyˌkynæn]

Key points:

j is like English y.
y and ä are front vowels; keep your tongue forward.
Every vowel is pronounced; nothing is silent.