Siskoni tekee kaakaota myös kylminä iltoina.

Siskoni means my sister.

It is made of:

• sisko = sister
• -ni = my

So:

• sisko → sister
• siskoni → my sister

Notice that the word changes slightly from sisko to sisko- / sisko + ni, giving siskoni.

In Finnish, possession is often shown with a possessive suffix attached to the noun instead of using a separate word like English my.

So instead of saying:

• my sister

Finnish can say:

• siskoni

The suffix -ni means my.

You can also say minun siskoni, which is more literally my sister, but very often just siskoni is enough.

The basic verb is tehdä, which often means to do or to make.

In this sentence, tekee means makes rather than does, because the object is kaakaota:

• tehdä kaakaota = to make cocoa / hot chocolate

Tekee is the third person singular present tense form:

• minä teen = I make
• sinä teet = you make
• hän tekee = he/she makes

So Siskoni tekee... means My sister makes...

Because kaakaota is in the partitive case.

The basic form is:

• kaakao = cocoa / hot chocolate

But after many verbs, especially when talking about an uncounted amount, Finnish often uses the partitive:

• tehdä kaakaota = to make cocoa / some cocoa / hot chocolate

This sounds natural because you are talking about the substance or drink, not one whole clearly bounded object.

Compare the idea in English:

• She is making cocoa
  not
• She is making a one-complete-cocoa

So the partitive fits well here.

The partitive often appears when the object is:

• an uncountable substance
• something indefinite
• something seen as an ongoing or not fully bounded action

Here, kaakaota is a drink/substance, so Finnish naturally uses the partitive.

That gives the sense:

• My sister makes cocoa / hot chocolate

If the sentence used a total object, the meaning would be more about a completed, specific item. But here the partitive is the normal choice.

Myös means also or too.

So the sentence says that besides whatever else is true, this is also true:

• Siskoni tekee kaakaota myös kylminä iltoina.
• My sister makes cocoa also on cold evenings.

In more natural English, that becomes something like:

• My sister also makes cocoa on cold evenings.
• My sister makes cocoa on cold evenings too.

Its position in Finnish can shift depending on what is being emphasized, but here it naturally connects with kylminä iltoina: also on cold evenings.

Kylminä iltoina is in the essive plural.

It comes from:

• kylmä = cold
• ilta = evening

Forms here:

• kylminä = as cold / on cold / during cold
• iltoina = on evenings / during evenings

Together:

• kylminä iltoina = on cold evenings

In this kind of time expression, the essive can mean something like during or on.

Because the phrase means on cold evenings, plural.

In Finnish, adjectives usually agree with the noun in number and case.

So both words are plural and both are in the essive:

• kylmä → kylminä
• ilta → iltoina

This agreement is very normal in Finnish.

Finnish often uses cases where English uses prepositions.

English says:

• on cold evenings

Finnish expresses that idea through the form kylminä iltoina, without a separate word for on.

So instead of:

• preposition + noun

Finnish often has:

• noun case ending

That is a very common difference between English and Finnish.

Not necessarily.

The Finnish present tense can mean:

• something happening now, or
• a habitual action, something that happens generally

In this sentence, because of kylminä iltoina (on cold evenings), it is most naturally understood as a habitual action:

• My sister makes cocoa on cold evenings.

So it sounds like something she tends to do, not just something happening at this exact moment.

Yes, Finnish word order is fairly flexible, although different orders can change emphasis.

The given sentence is neutral and natural:

• Siskoni tekee kaakaota myös kylminä iltoina.

You could also move myös:

• Myös siskoni tekee kaakaota kylminä iltoina.

That would suggest something more like:

• My sister too makes cocoa on cold evenings

So the basic meaning stays close, but the focus changes.

In real usage, kaakao often refers to the drink that English speakers might call hot chocolate or cocoa, depending on context.

So tekee kaakaota is best understood as:

• makes cocoa
• makes hot chocolate

The exact English choice depends on the translation style and context, but the Finnish itself is perfectly natural.

Yes—this sentence shows several very common Finnish patterns all at once:

1. Possessive suffix

   • siskoni = my sister

2. Present tense verb

   • tekee = makes

3. Partitive object

   • kaakaota = cocoa / hot chocolate as an uncounted substance

4. Essive time expression

   • kylminä iltoina = on cold evenings

5. Adjective-noun agreement

   • kylminä matches iltoina

So it is a short sentence, but it contains several very typical Finnish grammar features.