My aunt (who) I lived with.

Well, you really need to complete your sentence to really tell what's going on here grammatically. In any case, let me discuss a couple of things.

It would be okay to say 'My aunt I live with...' if you say it like this:

My aunt, I live with, is calling me for dinner.

Here, 'I live with' becomes a non essential element separated by commas,

NoctivagusHi.

I had a discussion auite some time ago with people claiming that they found the sentence "My aunt I live with" to be grammatically correct.

I can find no rule saying that "who" must not be left out here, as it could be in "The aunt I live with".

What are other oppinions?

To me "my aunt I live with" doesn't work...

Thank you for your answers.

I didn't give you a complete sentence as there wasn't one that I could remember. so "prefers tea" is as good as any.

I'm a little confused now as these answers seem to contradict each other. For me "My aunt I live with prefers tea" seems wrong in any case, with or without commas, as AlpheccaStars suggests.

AlpheccaStarsFor me "My aunt I live with prefers tea" seems wrong in any case, with or without commas, as AlpheccaStars suggests.

Yes. It's wrong with or without commas.

CJ

Nicole RasoolIt would be okay to say

My aunt, I live with, is calling me for dinner.

Here, 'I live with' becomes a non essential element separated by commas, and this makes the sentence correct.

No, it does not!

My aunt, who[m] I live with, is... is okay, but without the who[m], it's wrong.

NoctivagusHi.

I had a discussion auite some time ago with people claiming that they found the sentence "My aunt I live with" to be grammatically correct.

I can find no rule saying that "who" must not be left out here, as it could be in "The aunt I live with".

What are other oppinions?

To me "my aunt I live with" doesn't work...

Hi,

My aunt (that) I live with prefers tea.

This sounds fine to me. I take it to mean that you have another aunt. You don't live with this second aunt. And she doesn't prefer tea. You may even have several such aunts.

Thanks, but this is becoming really confusing.

Certainly I will stick to saying "My aunt who i live with...", but again some people claim that "My aunt I live with prefers tea" is fine, while others say it's worng.

NoctivagusThanks, but this is becoming really confusing.
... but again some people claim that "My aunt I live with prefers tea" is fine, while others say it's worng.

This shouldn't be surprising. It's just the way forums work! Not everyone agrees on the grammaticality of every construction.