Kahvitahra on vielä paidassa.

Because Finnish very often forms compound nouns by joining two nouns together.

• kahvi = coffee
• tahra = stain

So kahvitahra literally means coffee stain.

This is much more natural in Finnish than writing two separate words. English often uses noun + noun combinations with a space, but Finnish usually combines them into one word.

Here kahvitahra is the subject of the sentence.

The sentence structure is basically:

• kahvitahra = subject
• on = is
• vielä = still
• paidassa = in/on the shirt

The subject is in the nominative singular form: kahvitahra.

Because Finnish uses case endings where English often uses prepositions.

• paita = shirt
• paidassa = in the shirt / on the shirt

The ending -ssa / -ssä is the inessive case, which usually means in.

With clothing, Finnish often uses this case in situations where English says on:

• paidassa = on the shirt
• housuissa = in/on the trousers
• takissa = in/on the coat

So paidassa is the natural Finnish way to say that the stain is on the shirt.

This is a very common thing that English speakers notice.

In Finnish, a stain on clothing is often conceptualized as being in the fabric, not just sitting on top of it. So paidassa sounds natural.

If you said something more literally like paidan päällä (on top of the shirt), it would usually suggest something physically resting on the shirt rather than a stain absorbed into it.

So for stains, dirt, holes, marks, and similar things, paidassa is the normal choice.

Here vielä means still.

So it adds the idea that the coffee stain has not gone away yet.

Compare:

• Kahvitahra on paidassa. = The coffee stain is on the shirt.
• Kahvitahra on vielä paidassa. = The coffee stain is still on the shirt.

Depending on context, vielä can also mean yet, still, or sometimes even, but in this sentence still is the best match.

On is the 3rd person singular form of the verb olla, which means to be.

• minä olen = I am
• sinä olet = you are
• hän on = he/she is
• se on = it is

Since kahvitahra is singular, Finnish uses on.

Finnish has no articles. There is no direct equivalent of English a/an or the in ordinary sentences.

So kahvitahra can mean:

• a coffee stain
• the coffee stain

Which one is meant depends on context.

This is one of the big differences from English, and learners usually just have to get used to relying more on context.

Finnish word order is fairly flexible, although different orders can change the focus or emphasis.

The given sentence is natural and neutral:

• Kahvitahra on vielä paidassa.

But you could also say:

• Paidassa on vielä kahvitahra.

This version puts more focus on the shirt or presents the stain more like something found there.

Very roughly:

• Kahvitahra on vielä paidassa. = talking about the stain
• Paidassa on vielä kahvitahra. = talking about what is in/on the shirt

Both are grammatical, but they are not always identical in emphasis.

No, that would mean something like There is still coffee in the stain, which is a very different idea.

In kahvitahra, kahvi modifies tahra as part of a compound noun. It tells you what kind of stain it is.

So:

• kahvitahra = coffee stain
• not a stain that contains coffee right now

Compounds in Finnish are very important because they create meanings that are not the same as separate words in a sentence.

You would use the Finnish negative verb:

• Kahvitahra ei ole enää paidassa. = The coffee stain is no longer on the shirt.

Or more literally, if you only want to negate the original statement:

• Kahvitahra ei ole vielä paidassa.

But that sentence usually means The coffee stain is not on the shirt yet, which is probably not what you want in most contexts.

So if the meaning is it used to be there, but not now, Finnish normally uses enää:

• vielä = still
• enää = any longer / anymore

It is the inessive case.

The inessive ending is:

• -ssa
• -ssä

Which one appears depends on vowel harmony. Since paita has the front-vowel-compatible pattern for this ending, it becomes paidassa.

This case often means:

• in
• sometimes inside
• and in some contexts, especially with clothing, something closer to English on

So here:

• paita → paidassa

Then the subject would become plural, and the verb would also change:

• Kahvitahrat ovat vielä paidassa. = The coffee stains are still on the shirt.

Breakdown:

• kahvitahrat = coffee stains
• ovat = are
• paidassa = on/in the shirt

So Finnish marks plural both on the noun and on the verb.

Not in this sentence by itself. Here it simply means in/on the shirt.

In other contexts, paidassa can also be part of a phrase meaning someone is wearing a shirt, for example:

• Hän on paidassa.

That can sound incomplete on its own, but context can make it mean He/She is in a shirt.

In Kahvitahra on vielä paidassa, though, the meaning is clearly about the stain being on the shirt itself.