Learn Hardcore Greek: Στο σπίτι τρώω κυρίως απλό φαγητό με λαχανικά. - At home I mainly eat simple food with vegetables.

σε + το σπίτι → στο σπίτι
It is used before neuter singular nouns in the accusative and usually means at the / in the / to the.
Greek very often contracts σε + definite article:
- σε + το → στο
- σε + την → στην
- σε + τον → στον

So Στο σπίτι literally is In/At the house, but English normally says At home.

Why does Greek say στο σπίτι when English says “at home” without the?

Greek uses the definite article much more than English.

στο σπίτι literally: at the house / in the house
In English, the idiomatic expression is at home, no article.
In Greek, στο σπίτι is the normal way to say at home in this kind of sentence.

There is also είμαι σπίτι (without article or preposition) which also means I’m at home, but that is a different fixed pattern. In your sentence, because you also have a verb and a full clause, Στο σπίτι τρώω… is the natural choice.

Could the sentence start with Τρώω instead of Στο σπίτι? Does word order change the meaning?

You can say:

Στο σπίτι τρώω κυρίως απλό φαγητό με λαχανικά.
Τρώω κυρίως απλό φαγητό με λαχανικά στο σπίτι.

Both are grammatically correct and have basically the same overall meaning.

The difference is in emphasis:

Στο σπίτι τρώω… puts a bit more focus on where this is true (at home).
Τρώω… στο σπίτι puts the basic action I eat… first and adds the place after.

In everyday speech, both orders sound natural; Greek word order is flexible, and speakers use it to highlight different parts of the sentence.

What form is τρώω? Why does it have two ω?

Τρώω is the 1st person singular, present tense, active voice of the verb τρώω (to eat).

εγώ τρώω – I eat / I am eating
εσύ τρως – you eat
αυτός / αυτή / αυτό τρώει – he / she / it eats

The double ω is just how the verb is spelled in modern Greek; it is not two different sounds. You pronounce it as one long “o” sound: /tró-o/ (which in fast speech often sounds like just /tró/).

You normally do not need to say εγώ here, because τρώω already shows the subject I.

Why isn’t εγώ (I) written before τρώω?

Modern Greek is a pro‑drop language: the verb ending tells you who the subject is, so the subject pronoun is usually omitted.

Τρώω. – I eat. (the ω ending = 1st person singular)
Τρως. – You eat. (the ς ending = 2nd person singular)

You add εγώ only for emphasis or contrast:

Εγώ τρώω στο σπίτι, εσύ τρως έξω. – I eat at home, you eat out.

What does κυρίως mean, and where can it go in the sentence?

Κυρίως is an adverb meaning mainly / mostly / primarily.

Common positions include:

Στο σπίτι τρώω κυρίως απλό φαγητό…
Στο σπίτι κυρίως τρώω απλό φαγητό…
Κυρίως στο σπίτι τρώω απλό φαγητό…

All are possible, but:

After the verb (τρώω κυρίως…) is very typical and neutral.
Moving κυρίως changes the nuance slightly (what is “mostly”: the place, the action, or the kind of food), but in everyday speech people often don’t make a sharp distinction; context clarifies it.

How does απλό φαγητό work grammatically? Why is the adjective before the noun?

In Greek, adjectives usually come before the noun and must agree with it in:

gender
number
case

Here:

φαγητό – neuter, singular, accusative (what do I eat? → the object)
απλό – neuter, singular, accusative to match φαγητό

So απλό φαγητό = simple/plain food.

You can sometimes put the adjective after the noun (φαγητό απλό), but that is less neutral and can sound more marked or stylistic. The default order is adjective + noun.

Why is there no article before απλό φαγητό? Why not το απλό φαγητό?

Without an article, απλό φαγητό is non‑specific and general:

απλό φαγητό – simple food in general, the kind of food I typically eat

With the article, το απλό φαγητό would mean the simple food (a specific, known dish or category already mentioned).

In your sentence, you are talking about your typical diet, not one particular dish, so Greek omits the article, similar to English I eat simple food.

What does με mean here, and how is με λαχανικά different from μαζί με λαχανικά?

Με is the basic preposition meaning with.

με λαχανικά – with vegetables (the dish includes vegetables)
με τα λαχανικά – with the vegetables (specific vegetables already known in context)

Μαζί με literally means together with and emphasizes accompanying things or people:

τρώω κρέας μαζί με λαχανικά – I eat meat together with vegetables (stressing that you eat them as separate parts of a meal)

In your sentence, με λαχανικά is the normal, concise way to say the food contains or comes with vegetables.

What is λαχανικά grammatically? Why that ending?

Λαχανικά is:

the plural of λαχανικό (vegetable)
neuter, plural, accusative here

It is the object of the preposition με, which takes the accusative:

με λαχανικά – with vegetables

For neuter nouns, nominative and accusative plural have the same form (λαχανικά), so context tells you the function in the sentence.

Can I say Στο σπίτι τρώω κυρίως απλό φαγητό με τα λαχανικά? Does adding τα change the meaning?

You can say it, but the meaning changes slightly.

με λαχανικά – with vegetables (in general, an unspecified quantity/type)
με τα λαχανικά – with the vegetables (specific vegetables both speaker and listener have in mind, e.g. the ones already on the table or already mentioned)

In a general statement about your habits (what you usually eat at home), με λαχανικά is more natural, because you mean vegetables in general, not some specific, known vegetables.