Πήγα να πέσω στο πεζοδρόμιο, γιατί περπατούσα γρήγορα και δεν κοίταγα κάτω.

This is a very common Greek pattern:

πάω / πήγα + να + verb

It often does not mean literal movement. In many everyday sentences, it means that something was about to happen, often unexpectedly.

So:

• Πήγα να πέσω = I almost fell
• literally, word-for-word, it looks like I went to fall
• but idiomatically it means I came close to falling

You can think of it as similar to:

• I nearly fell
• I was about to fall

This is a fixed and very useful expression in spoken Greek.

Examples:

• Πήγα να γελάσω. = I almost laughed.
• Πήγε να κλάψει. = She almost cried.
• Πήγα να τρελαθώ. = I almost went crazy.

So in this sentence, πήγα να πέσω is best learned as a chunk meaning I almost fell.

After να, Greek usually uses the subjunctive form, not the dictionary form.

The dictionary form is:

• πέφτω = I fall

But after να, you need the appropriate subjunctive form:

• να πέσω

Here, πέσω is the aorist subjunctive form of πέφτω.

So:

• πέφτω = I fall / I am falling
• να πέσω = to fall / that I fall / to end up falling, depending on context

In πήγα να πέσω, the aorist subjunctive fits well because it refers to a single completed event that almost happened: one fall.

This is a very important Greek tense contrast.

• πήγα is aorist: it points to a single event
• περπατούσα and κοίταγα are imperfect: they describe ongoing background actions

So the sentence works like this:

• Πήγα να πέσω = one near-accident, one moment
• γιατί περπατούσα γρήγορα και δεν κοίταγα κάτω = the ongoing circumstances behind it

This is very similar to English:

• I almost fell
• because I was walking quickly and wasn’t looking down

The imperfect is used here because the speaker is describing what they were doing at the time.

No, they are different tenses and give different meanings.

• περπατούσα = I was walking / I used to walk
• περπάτησα = I walked

In this sentence, περπατούσα means I was walking, because it describes an action in progress when the near fall happened.

Compare:

• Περπατούσα γρήγορα. = I was walking quickly.
• Περπάτησα γρήγορα. = I walked quickly.

The imperfect περπατούσα gives the sense of duration or background.

For the same reason as περπατούσα.

• κοίταγα is imperfect: I was looking / I was paying attention
• κοίταξα is aorist: I looked

Here the speaker means:

• I wasn’t looking down as an ongoing situation

not:

• I didn’t look down once

So:

• δεν κοίταγα κάτω = I wasn’t looking down
• δεν κοίταξα κάτω = I didn’t look down

The first one fits the context much better because it describes the background cause of the near fall.

Yes, κοίταγα is correct. Κοίταζα is also correct.

These are two common imperfect forms of κοιτάζω:

• κοίταγα
• κοίταζα

Both mean the same thing: I was looking.

This kind of variation is common in Modern Greek, especially in everyday speech. Some forms may sound more natural in certain regions or to certain speakers, but both are standard and widely understood.

So:

• δεν κοίταγα κάτω
• δεν κοίταζα κάτω

Both are fine.

Here στο is σε + το.

• σε often means in, at, on, to
• το πεζοδρόμιο = the sidewalk / pavement

So στο πεζοδρόμιο can mean:

• on the sidewalk
• onto the sidewalk
• to the sidewalk

The exact English choice depends on context.

In this sentence, with πέσω, English usually prefers:

• I almost fell on the sidewalk or
• I almost fell onto the sidewalk

If the speaker was already walking there, on the sidewalk is the most natural translation. If the emphasis is on the motion of falling down toward it, onto the sidewalk can also work.

Because πεζοδρόμιο is a neuter noun.

Greek definite articles change for gender:

• masculine: ο / τον / στον
• feminine: η / την / στην
• neuter: το / στο

Since πεζοδρόμιο is neuter:

• το πεζοδρόμιο
• στο πεζοδρόμιο

So στον πεζοδρόμιο would be wrong.

Here κάτω means down.

So:

• δεν κοίταγα κάτω = I wasn’t looking down

It is being used as an adverb, not as an adjective or noun.

Very common examples:

• Κοίτα κάτω. = Look down.
• Έπεσε κάτω. = He/She fell down.
• Το άφησα κάτω. = I left it down/below/on the floor, depending on context

In your sentence, κάτω tells you the direction of the speaker’s gaze.

Greek often leaves out subject pronouns because the verb ending already shows who the subject is.

For example:

• πήγα = I went
• περπατούσα = I was walking
• κοίταγα = I was looking

So Greek does not need to say εγώ unless there is special emphasis or contrast.

The sentence could say:

• Εγώ πήγα να πέσω...

but that would sound more emphatic, like:

• I almost fell...
• As for me, I almost fell...

In neutral speech, leaving out the pronoun is normal.

Γιατί here means because.

It introduces the reason:

• γιατί περπατούσα γρήγορα και δεν κοίταγα κάτω
• because I was walking quickly and wasn’t looking down

Greek γιατί can mean both:

• because
• why

Examples:

• Δεν ήρθα γιατί ήμουν άρρωστος. = I didn’t come because I was sick.
• Γιατί άργησες; = Why were you late?

So you have to understand it from context. In your sentence, it clearly means because.

Yes. Greek often uses παραλίγο to express almost.

For example:

• Παραλίγο να πέσω στο πεζοδρόμιο.

This also means:

• I almost fell on the sidewalk.

Both are natural:

• Πήγα να πέσω...
• Παραλίγο να πέσω...

There can be a slight difference in tone:

• πήγα να πέσω often sounds very conversational and vivid
• παραλίγο να πέσω is also very common and directly expresses almost

A learner should understand both.

The word order is quite natural and neutral.

• Πήγα να πέσω στο πεζοδρόμιο
• γιατί περπατούσα γρήγορα
• και δεν κοίταγα κάτω

Greek word order is more flexible than English, but this order is straightforward:

1. main event
2. reason
3. extra detail

You could move things around for emphasis, for example:

• Γιατί περπατούσα γρήγορα και δεν κοίταγα κάτω, πήγα να πέσω στο πεζοδρόμιο.

But the original version is the most natural for everyday speech.

Usually, yes.

πεζοδρόμιο is the normal Greek word for:

• sidewalk in American English
• pavement in British English

So depending on the learner’s variety of English:

• στο πεζοδρόμιο = on the sidewalk
• στο πεζοδρόμιο = on the pavement

It refers to the part of the street meant for pedestrians.