Στο γιαούρτι βάζω καρύδια και αμύγδαλα, γιατί μου αρέσουν περισσότερο.

Στο is a contraction of σε + το.

• σε = in / at / to
• το = the for a neuter singular noun

So στο γιαούρτι literally looks like in/to the yogurt, but in this sentence it naturally means in the yogurt or into the yogurt.

Greek often uses σε in places where English uses in, into, or to, depending on the verb and context.

Because γιαούρτι is a neuter singular noun, and after σε + το the noun stays in the accusative singular, which for many neuter nouns looks the same as the nominative.

So:

• το γιαούρτι = the yogurt
• στο γιαούρτι = in the yogurt

There is no visible change in the noun here, which is very common with neuter nouns.

It can mean both, depending on context.

βάζω is a very common verb meaning:

• put
• place
• add

In this sentence, English would usually say I add walnuts and almonds to yogurt or I put walnuts and almonds in yogurt. Both are good translations.

So here βάζω is being used in the everyday sense of adding something to food.

Greek often leaves out the article when talking about ingredients or things in a general, non-specific way.

So:

• βάζω καρύδια και αμύγδαλα = I add walnuts and almonds

This sounds natural when you mean those foods in general, not specific walnuts or specific almonds.

You could sometimes hear articles in other contexts, but here the article-free version is very natural.

They are in the accusative plural, because they are the direct objects of βάζω.

• βάζω τι; = I put what?
• καρύδια και αμύγδαλα

Both nouns are neuter plural, and for many neuter nouns the nominative plural and accusative plural look the same.

So even though they are objects, their forms may look familiar from dictionary forms.

Because the thing being liked is plural:

• καρύδια και αμύγδαλα = walnuts and almonds

The verb αρέσω works differently from English like. It literally behaves more like:

• they are pleasing to me

So:

• μου αρέσει = I like it / it pleases me
• μου αρέσουν = I like them / they please me

Since καρύδια και αμύγδαλα is plural, Greek uses the plural form αρέσουν.

Because αρέσω does not work like the English verb like.

In Greek, the person who experiences the liking is usually in an indirect-object form:

• μου = to me

And the thing liked is the grammatical subject:

• καρύδια και αμύγδαλα = the things that please

So:

• μου αρέσουν literally = they are pleasing to me
• natural English = I like them

This is one of the most important patterns for learners to get used to.

περισσότερο means more.

In this sentence, γιατί μου αρέσουν περισσότερο means:

• because I like them more
• or because I prefer them more

It usually implies a comparison with something else that is understood from context, such as other toppings or other things you could put in yogurt.

It does not necessarily mean I like walnuts more than almonds. It more naturally means I like walnuts and almonds more than other options.

Yes, very often.

Greek commonly uses both:

• περισσότερο
• πιο πολύ

So you could also hear:

• γιατί μου αρέσουν πιο πολύ

Both are natural in everyday Greek.
περισσότερο can sound a little more neutral or standard in some contexts, while πιο πολύ is also extremely common in speech.

Greek word order is more flexible than English word order.

Both are possible:

• Στο γιαούρτι βάζω καρύδια και αμύγδαλα
• Βάζω καρύδια και αμύγδαλα στο γιαούρτι

Starting with Στο γιαούρτι puts a little more focus on the yogurt, as the setting or topic. It can sound like:

• As for yogurt, I add walnuts and almonds...
• In yogurt, I put walnuts and almonds...

So the fronted phrase helps organize the sentence, not just give location.

γιατί can mean either:

• because
• why

The meaning depends on the sentence.

Here it introduces a reason:

• γιατί μου αρέσουν περισσότερο = because I like them more

If it were a question, the structure and punctuation would show that:

• Γιατί βάζεις καρύδια στο γιαούρτι; = Why do you put walnuts in yogurt?

So context tells you which meaning is intended.

No, not naturally in this sentence.

With αρέσει / αρέσουν, the person who likes something is usually expressed with a weak pronoun such as:

• μου = to me
• σου = to you
• του/της = to him/her

So:

• μου αρέσουν = I like them

If you remove μου, the sentence loses the person who is doing the liking, so it would no longer mean what you want.

Yes, it sounds natural and idiomatic.

It is a very normal way to say that you add those ingredients to yogurt and that the reason is your preference for them.

A very close everyday English version would be:

• I put walnuts and almonds in yogurt because I like them more.

And a very natural Greek-speaking alternative might also be:

• Βάζω καρύδια και αμύγδαλα στο γιαούρτι, γιατί μου αρέσουν περισσότερο.

Both word orders are fine.