Epäilen punaista painiketta, koska peili yrittää harhauttaa meitä.

In Finnish, the verb ending already tells you the subject.

• epäilen = I suspect
• The ending -n shows first person singular.

So minä is usually unnecessary unless you want emphasis or contrast.

• Epäilen punaista painiketta. = I suspect the red button.
• Minä epäilen punaista painiketta. = I’m the one who suspects the red button. / extra emphasis

Because epäillä usually takes its object in the partitive case.

The basic dictionary forms are:

• punainen = red
• painike = button

In this sentence they become:

• punaista
• painiketta

This is the partitive singular. So:

• epäillä jotakin = to suspect something
• epäilen painiketta = I suspect the button

Since the adjective must agree with the noun, both words go into the same case:

• punainen painike → punaista painiketta

Adjectives in Finnish agree with the noun they describe in case and number.

So if painiketta is in the partitive singular, the adjective must also be in the partitive singular:

• punainen painike = a red button
• punaista painiketta = a red button / the red button, as a partitive object

This kind of agreement is completely normal in Finnish:

• iso talo → isoa taloa
• sininen auto → sinistä autoa

Because harhauttaa takes an object, and here us is the object.

• me = we (subject form)
• meidät / meitä = object forms, depending on grammar

In this sentence, the object is partitive:

• harhauttaa meitä = mislead us

So you cannot use me, because that would be the subject form.

This is a very common learner question. Finnish object marking can be tricky.

Here, harhauttaa is being used in a way that takes a partitive object, so we get:

• harhauttaa meitä

Partitive objects are common when the action is viewed as ongoing, incomplete, or when the verb normally allows/requires partitive in that context. With verbs like rakastaa, odottaa, auttaa, harhauttaa, partitive objects are very common.

So:

• harhauttaa meitä = to mislead us

rather than meidät.

Koska means because in this sentence.

It introduces the reason:

• Epäilen punaista painiketta = I suspect the red button
• koska peili yrittää harhauttaa meitä = because the mirror is trying to mislead us

Be careful: koska can also mean when in some contexts, but here it clearly means because.

Yrittää is the dictionary form meaning to try.

Here it is in the third person singular present tense:

• minä yritän = I try
• sinä yrität = you try
• hän/se yrittää = he/she/it tries

The subject is peili (the mirror), which is singular, so the verb is:

• peili yrittää = the mirror tries / is trying

This is a normal Finnish verb pattern.

• yrittää = to try
• It is followed by another verb in the basic infinitive form.
• harhauttaa = to mislead

So:

• yrittää harhauttaa = to try to mislead

This works much like English:

• He tries to help → Hän yrittää auttaa
• The mirror tries to mislead us → Peili yrittää harhauttaa meitä

Because it is the subject of the clause:

• peili yrittää harhauttaa meitä

Subjects are often in the nominative case, which is the basic dictionary form.

So:

• peili = mirror
• peili yrittää = the mirror tries

No special ending is needed here.

Finnish word order is more flexible than English word order, because cases show grammatical roles.

The neutral order here is:

• Epäilen punaista painiketta, koska peili yrittää harhauttaa meitä.

But other orders are possible for emphasis. For example:

• Koska peili yrittää harhauttaa meitä, epäilen punaista painiketta.

This puts more focus on the reason first.

Still, the original version sounds very natural and straightforward.

Because koska introduces a subordinate clause, and Finnish normally separates that clause with a comma.

So:

• main clause: Epäilen punaista painiketta
• subordinate clause: koska peili yrittää harhauttaa meitä

That is why you write:

• Epäilen punaista painiketta, koska peili yrittää harhauttaa meitä.

This is standard Finnish punctuation.

Often yes, but it is worth learning the Finnish pattern rather than assuming it works exactly like English in every case.

epäillä can mean things like:

• to suspect
• to doubt
• to be suspicious of

Examples:

• Epäilen häntä. = I suspect him/her.
• Epäilen tätä suunnitelmaa. = I’m suspicious of this plan. / I doubt this plan.

So in your sentence, epäilen punaista painiketta suggests suspicion toward the red button.

A rough English-friendly guide would be:

• Epäilen ≈ EH-pie-len
• punaista ≈ POO-nai-sta
• painiketta ≈ PIE-ni-ket-ta
• koska ≈ KOS-ka
• peili ≈ PAY-li
• yrittää ≈ UH-rut-TAA (very rough; the Finnish y and ä do not exist exactly in English)
• harhauttaa ≈ HAR-howt-taa
• meitä ≈ MAY-tä

A few key pronunciation points:

• ai sounds roughly like the i in fine
• ei sounds roughly like ay in say
• double consonants and double vowels are important
• ä is a front vowel, somewhat like the a in British cat, but not exactly
• Finnish stress is usually on the first syllable

So the sentence stress pattern begins:

• E-päi-len PU-nais-ta PAI-ni-ket-ta...