Learn Hardcore Greek: Αν δεν πληρώσεις το πρόστιμο, μπορεί να πας στο δικαστήριο με τον δικηγόρο σου. - If you don’t pay the fine, you may have to go to court with your lawyer.

πληρώνεις = present indicative: you are paying / you pay (habitually)
(να) πληρώσεις = aorist subjunctive: you (should) pay / you (will) pay (once, as a whole action)

In Greek, after αν (if), you normally use the subjunctive with να understood or omitted in many grammars:

Αν πληρώσεις το πρόστιμο… – If you pay the fine (once, that specific act)…

Using πληρώνεις here would sound wrong, because the sentence talks about one specific future action (that one payment), not a general habit.

What exactly does Αν mean here? Is it the same as όταν?

Here Αν means “if”, introducing a condition.

Αν δεν πληρώσεις… = If you don’t pay…

It is not the same as όταν (when):

Όταν δεν πληρώνεις τα πρόστιμα, έχεις προβλήματα.
When you don’t pay fines (whenever that happens), you have problems.

Αν = condition (maybe yes, maybe no).
Όταν = time (whenever / when something happens).

Why is the negation δεν placed before πληρώσεις and not after it?

In Greek, the basic negation word in standard statements is δεν, and it almost always comes directly before the verb:

δεν πληρώνω – I don’t pay
δεν πληρώσεις – you don’t pay (in this conditional construction)
δεν πάω – I don’t go

So the normal order is δεν + verb.
You generally can’t say πληρώσεις δεν in modern standard Greek.

What does μπορεί mean here? Why not μπορείς να πας?

In this sentence, μπορεί is used impersonally and means “it is possible (that)”:

…μπορεί να πας στο δικαστήριο…
= …you may go to court / it is possible that you will go to court…

So the structure is:

μπορεί + να + subjunctive = it may be that / it is possible that…

If you say μπορείς να πας, that usually means “you are able to go / you are allowed to go” (ability or permission), not objective possibility.

μπορεί να πας = maybe you will go (possibility)
μπορείς να πας = you can go / you’re allowed to go (permission/ability)

Here, because we’re talking about a possible legal consequence, impersonal μπορεί (possibility) is the natural choice.

Is να πας a future tense? How does it work?

Να πας is subjunctive mood, not a future tense. It’s formed with να + subjunctive:

να πας – (that you) go
να πληρώσεις – (that you) pay

In this sentence:

μπορεί να πας = it is possible (that you) go → you may go / you might go

Greek often uses να + subjunctive to talk about:

possibility (after μπορεί)
purpose (after για να)
wishes, orders, etc.

Future is usually formed with θα + verb (e.g. θα πας = you will go), but after μπορεί you use να + subjunctive, not θα.

What is the role of το in το πρόστιμο?

Το is the definite article, neuter singular, meaning “the”:

πρόστιμο – fine (a fine, any fine)
το πρόστιμο – the fine (a specific one both speaker and listener know about)

Greek almost always uses the definite article when English does, and often even when English does not. So:

Πλήρωσε το πρόστιμο.
Literally: He paid the fine. (That particular fine we’re talking about.)

What case is το πρόστιμο in, and why?

Το πρόστιμο is in the accusative case (neuter singular).

In πληρώσεις το πρόστιμο, το πρόστιμο is the direct object of the verb πληρώσεις (what you pay), so it must be in accusative.

Pattern:

(Εσύ) πληρώνεις το πρόστιμο.
(You) pay the fine.
Subject: εσύ (nominative)
Object: το πρόστιμο (accusative)

Why is it στο δικαστήριο and not σε το δικαστήριο?

Στο is a contraction of:

σε + το → στο

This contraction is obligatory in normal speech and writing:

σε το σπίτι → στο σπίτι (to the house)
σε το δικαστήριο → στο δικαστήριο (to the court / at court)

So στο δικαστήριο literally means “in/to the court” and is how you must say it in modern Greek.

What does δικαστήριο mean exactly, and is it countable?

Δικαστήριο is a neuter noun meaning:

court (institution / place of justice)
sometimes trial / court session (by metonymy, depending on context)

It is countable:

ένα δικαστήριο – one court
δύο δικαστήρια – two courts

In this sentence, στο δικαστήριο means “to court” / “to the court”, i.e. appearing before a court as a legal procedure.

Why is it τον δικηγόρο and not ο δικηγόρος?

Ο δικηγόρος is nominative singular masculine – the form used for the subject:

Ο δικηγόρος μιλάει. – The lawyer is speaking.

Here, τον δικηγόρο is in the accusative case, because it’s the object of the preposition με (with):

με τον δικηγόρο – with the lawyer
(preposition με
- accusative)

So:

ο δικηγόρος (nominative – subject)
τον δικηγόρο (accusative – object, after prepositions like με)

How does the possessive σου work in τον δικηγόρο σου?

Σου is the 2nd person singular possessive pronoun = “your”.
In Greek it usually comes after the noun (and after the article, if there is one):

ο δικηγόρος σου – your lawyer
το σπίτι σου – your house
το βιβλίο σου – your book

So με τον δικηγόρο σου literally is “with the lawyer of-you”, but in English we say “with your lawyer”.

Could the word order change, for example: Αν δεν πληρώσεις το πρόστιμο, με τον δικηγόρο σου μπορεί να πας στο δικαστήριο?

That word order is grammatically possible, but it sounds unnatural and marked in everyday speech.

The neutral, most natural order is exactly what you have:

Αν δεν πληρώσεις το πρόστιμο, μπορεί να πας στο δικαστήριο με τον δικηγόρο σου.

Greek word order is flexible, but moving με τον δικηγόρο σου before μπορεί here would usually be reserved for strong emphasis on “with your lawyer”, and would still sound a bit odd in this context.

Is the sentence formal or informal? How would I say it politely to a stranger?

The sentence uses 2nd person singular (πληρώσεις, να πας, σου), which is informal (used with friends, family, people you “tutoyer”).

To be polite or formal (addressing one stranger or several people), you use 2nd person plural:

Αν δεν πληρώσετε το πρόστιμο, μπορεί να πάτε στο δικαστήριο με τον δικηγόρο σας.

Changes:

πληρώσεις → πληρώσετε
να πας → να πάτε
σου → σας

This is the form you’d expect from an officer, a clerk, or a sign addressing the public.