Γέμισε την κανάτα με κρύο νερό, και εγώ θα ξεπαγώσω το ψωμί.

Yes. In this sentence, Γέμισε is the singular informal imperative of γεμίζω (to fill), so it means Fill!

So:

• Γέμισε = Fill (said to one person, informal)

A learner may notice that γέμισε can also look like a past-tense form in other contexts, but here the sentence structure makes it clear that it is a command.

If you were speaking to:

• more than one person: Γεμίστε την κανάτα...
• one person formally: Greek also uses the plural, so again Γεμίστε...

Because την κανάτα is the direct object of the verb Γέμισε.

Greek usually uses the definite article much more often than English does. So where English might say:

• Fill the jug

Greek says:

• Γέμισε την κανάτα

Here:

• η κανάτα = the jug / pitcher (nominative)
• την κανάτα = the jug / pitcher (accusative, because it is the object)

So the article changes form to match the case.

This is actually a normal feminine noun pattern in Greek.

The dictionary form is:

• η κανάτα = the jug

In the accusative singular, it becomes:

• την κανάτα

In this noun, the ending of the noun itself does not change between nominative and accusative singular; the article shows the case clearly.

So:

• η κανάτα = subject form
• την κανάτα = object form

This is very common with many feminine nouns in -α.

Because νερό is a neuter singular noun, and the adjective must agree with it.

So:

• νερό = neuter singular
• κρύο = neuter singular form of cold

That gives:

• κρύο νερό = cold water

Compare:

• κρύος καφές = cold coffee (masculine)
• κρύα σούπα = cold soup (feminine)
• κρύο νερό = cold water (neuter)

Because Greek often leaves out the article when speaking about a substance or material in a general way.

So:

• με κρύο νερό = with cold water

This sounds natural when the meaning is simply use cold water.

If you added the article, it would usually sound more specific:

• με το κρύο νερό = with the cold water / with that cold water

So in this sentence, no article is the natural choice.

Here με means with, introducing what the jug should be filled with.

So:

• Γέμισε την κανάτα με κρύο νερό
  = Fill the jug with cold water

This is the same basic pattern as in English:

• fill something with something

In Greek:

• γεμίζω κάτι με κάτι

Examples:

• Γέμισε το ποτήρι με χυμό. = Fill the glass with juice.
• Γέμισα το μπολ με ρύζι. = I filled the bowl with rice.

No, εγώ is not grammatically necessary, because the verb already shows the person:

• θα ξεπαγώσω already means I will defrost

Greek often omits subject pronouns unless there is a reason to include them.

Here εγώ adds emphasis or contrast, something like:

• and I will defrost the bread
• and as for me, I’ll defrost the bread
• and I’ll take care of the bread

So και εγώ feels a bit more like dividing tasks:

• You fill the jug..., and I’ll defrost the bread.

Greek commonly forms the future with θα plus a verb form.

Here:

• θα = future marker
• ξεπαγώσω = the form used here for a single complete action

So:

• θα ξεπαγώσω = I will defrost

This is the normal way to express a simple future action.

The full idea is:

• και εγώ θα ξεπαγώσω το ψωμί
  = and I will defrost the bread

This is a question about aspect, which is very important in Greek.

Very roughly:

• ξεπαγώνω = imperfective stem
• ξεπαγώσω = perfective stem

In this sentence, θα ξεπαγώσω presents the action as one whole completed event:

• I’ll defrost the bread

That fits well because it is a simple, one-time task.

Greek often uses:

• θα + perfective form for a single complete future action

So θα ξεπαγώσω το ψωμί sounds like I’ll defrost the bread (and get that done).

Because ψωμί is the direct object of ξεπαγώσω.

The basic noun is:

• το ψωμί = the bread

It is a neuter noun, and in the singular the nominative and accusative forms are the same here, so it stays:

• το ψωμί

That means:

• το ψωμί can be either subject or object, depending on the sentence

In this sentence it is the object:

• θα ξεπαγώσω το ψωμί = I will defrost the bread

Yes. Greek word order is more flexible than English word order.

This sentence could be rearranged in different ways depending on emphasis, for example:

• Και εγώ θα ξεπαγώσω το ψωμί.
• Το ψωμί θα το ξεπαγώσω εγώ.
  (more emphatic: I’ll be the one to defrost the bread)

But the original version:

• Γέμισε την κανάτα με κρύο νερό, και εγώ θα ξεπαγώσω το ψωμί.

is very natural and straightforward.

Greek uses word order partly for focus and emphasis, not just for basic grammar.

Yes. Γέμισε is the singular informal command, used when speaking to one person casually.

To speak:

• to more than one person
• or to one person politely/formally

Greek uses the plural imperative:

• Γεμίστε την κανάτα με κρύο νερό...

So:

• Γέμισε = fill (one person, informal)
• Γεμίστε = fill (plural or formal)

It can cover the idea of defrost, thaw, or unfreeze, depending on context.

So:

• ξεπαγώνω / ξεπαγώσω = to make something no longer frozen

With food, English may use:

• defrost the bread
• thaw the bread

Both are close in meaning here.

Greek does not always draw exactly the same distinction English does between defrost and thaw, so context decides the most natural translation.

Because the sentence joins two coordinated clauses:

• Γέμισε την κανάτα με κρύο νερό
• και εγώ θα ξεπαγώσω το ψωμί

The comma helps separate the two actions clearly:

• You do this, and I’ll do that

In short, it marks a pause between two linked parts of the sentence.