A lot of the time I hear my students say, 'I eat already.'

I eat already.

And I understand why because in many languages if you say 'I eat already,' it's correct grammar.

But when you translate that from your language into English, it's not correct grammar.

So let's start off with the question. What's the question for this answer?

It's 'Have you eaten already?'

So then what's the correct answer?

The correct answer is 'I have eaten already.'

I have eaten already.

Because the question uses 'have' and 'eaten' so with the answer, we also must use 'have' and 'eaten'.

I have eaten already.

And when a native speaker says this really quickly, it sounds like this.

I'veaten already. I'veaten already.

We don't say 'I have'. We say 'I've'.

And we don't say 'I've eaten.'

The 'I've' and the 'eaten' come together. I'veaten already. I'veaten already.

Now you try. I've eaten already.

So the next time you want to say you have eaten already, you can say 'I'veaten already.' I'veaten already.