Mi preskaŭ renversis la akvon sur la tablon.

Because -is marks the past tense in Esperanto.

So:

• renversas = overturns / spills
• renversis = overturned / spilled
• renversos = will overturn / will spill

In Mi preskaŭ renversis la akvon sur la tablon, the speaker is talking about something that almost happened in the past.

Preskaŭ means almost.

It tells you that the action came close to happening, but did not actually happen. So the idea is:

• Mi renversis la akvon... = I spilled the water...
• Mi preskaŭ renversis la akvon... = I almost spilled the water...

In other words, the speaker nearly did it, but didn’t.

Renversi often means to tip over, to overturn, or to spill by knocking/tipping something.

In this sentence, it suggests causing the water to go out by overturning or upsetting something. In everyday English, the natural translation is often just spill.

So here renversis la akvon means something like:

• spilled the water
• knocked the water over
• caused the water to overturn/spill

Because la akvon is the direct object of the verb, so it takes the accusative -n.

The verb renversi is doing something to the water, so akvo becomes akvon.

• la akvo = the water
• la akvon = the water (as the direct object)

This is one of the most important uses of -n in Esperanto.

La means the. It shows that we are talking about a specific water, not just water in general.

So:

• akvon = water
• la akvon = the water

In many real situations, English and Esperanto both often use the when the context makes the water identifiable: for example, the water in a glass, cup, or bottle.

Because sur la tablon shows movement toward a surface: onto the table.

This is a very common Esperanto pattern:

• sur la tablo = on the table
• sur la tablon = onto the table

The -n here does not mark a direct object. Instead, it shows direction or destination.

So the sentence means the water would have gone onto the table, not that it was already sitting on the table.

They have -n for different reasons.

• akvon: direct object of renversis
• tablon: direction after the preposition sur

So Esperanto uses -n in at least these two important ways:

1. Direct object
   • Mi vidas la hundon. = I see the dog.
2. Direction / motion toward
   • Mi iras en la domon. = I go into the house.

In your sentence, both uses happen at the same time.

No. It means the water was moving or would move onto the table.

If you said sur la tablo, that would describe a location:

• La akvo estas sur la tablo. = The water is on the table.

But in your sentence, the idea is that the water nearly got spilled onto the table, so sur la tablon is the right form.

Esperanto word order is fairly flexible, but the usual order here is natural:

• Mi preskaŭ renversis la akvon sur la tablon.

Placing preskaŭ before the verb makes it clear that the speaker almost did the action.

Other word orders may be possible for emphasis, but this version is straightforward and normal for learners to model.

Yes, it is understandable and natural enough.

However, depending on the exact situation, Esperanto speakers might sometimes choose a different verb for a more specific image.

For example:

• verŝi often means pour or spill (liquid)
• renversi often suggests tipping over / overturning

So if the idea is specifically that liquid almost got spilled, some speakers might also say something like:

• Mi preskaŭ verŝis la akvon sur la tablon.

But Mi preskaŭ renversis la akvon sur la tablon is still a normal and understandable sentence.

Not in a strange literal sense. In practice, it means the speaker almost caused the water to spill onto the table.

Languages do not always phrase these situations exactly the same way. English often says:

• I almost spilled the water on the table.

Esperanto can express the same idea with renversi la akvon or sometimes with other verbs depending on nuance. The important thing is the overall meaning: the water nearly ended up spilled onto the table.