Tai tôi đau.

In Vietnamese, possession is usually expressed as:

noun + possessor

So:

• tai tôi = my ear
• literally, it looks like ear I

This is normal Vietnamese word order, not unusual or poetic. Other examples:

• nhà tôi = my house
• bạn tôi = my friend
• mẹ tôi = my mother

So tai tôi đau is built around tai tôi = my ear.

No. Vietnamese often does not use a word equivalent to is in sentences with adjectives or physical states.

So:

• Tai tôi đau literally follows the pattern my ear painful/hurts
• It naturally means My ear hurts

This is very common in Vietnamese. For example:

• Tôi mệt = I am tired
• Cô ấy đẹp = She is beautiful

So there is no missing word here.

Đau is a very common Vietnamese word meaning painful, to hurt, or to ache, depending on context.

In a sentence like Tai tôi đau, it behaves like a stative word describing a condition:

• tai tôi đau = my ear hurts / my ear is painful

English usually forces you to choose between a verb and an adjective, but Vietnamese is often more flexible in this area.

You will also see đau in expressions like:

• đau đầu = headache / head hurts
• đau bụng = stomachache / stomach hurts
• đau chân = leg hurts

Yes, Tai tôi đau is grammatical and understandable, but in everyday speech many speakers would more naturally say:

• Tôi đau tai
• Tôi bị đau tai

The difference is mainly one of focus and style:

• Tai tôi đau = My ear hurts with focus on my ear
• Tôi đau tai = more neutral, everyday I have ear pain / My ear hurts
• Tôi bị đau tai = also natural, sometimes slightly more explicit about suffering from ear pain

So the original sentence is fine, but it may sound a little more like As for my ear, it hurts.

By itself, tai can be understood generally as ear or ears, depending on context.

So Tai tôi đau could mean:

• My ear hurts
• My ears hurt

If you want to be specific, Vietnamese can add more information:

• một bên tai tôi đau = one of my ears hurts
• tai trái tôi đau = my left ear hurts
• tai phải tôi đau = my right ear hurts
• hai tai tôi đau = both my ears hurt

Vietnamese often leaves number unspecified when the context makes it clear enough.

Vietnamese does not have a separate possessive adjective like English my in the same way. Instead, it usually expresses possession with the structure:

thing + pronoun

So:

• tai tôi = my ear
• sách tôi = my book
• xe tôi = my vehicle / my bike / my car

The pronoun tôi still means I / me, but after a noun it functions like my.

A rough pronunciation guide is:

• tai ≈ tie
• tôi ≈ somewhat like toy, but with a pure Vietnamese vowel
• đau ≈ somewhat like dow in down without the final n

A few helpful notes:

• All three words here have the level tone because they have no tone marks.
• đ is pronounced like an English d.
• The ô in tôi is a different vowel letter from plain o, so the spelling matters.

A rough full approximation is:

tie toy dow

But it is only approximate, since Vietnamese vowels are more precise than English ones.

No, not here.

Body parts usually do not need a classifier in a simple sentence like this. So:

• Tai tôi đau is fine
• Tôi đau tai is fine

You may sometimes hear cái tai, but that usually sounds more concrete, emphatic, or object-like, and it is not necessary in this basic sentence.

So for a learner, the safest choice is:

• tai by itself for ear

Yes. Tai is the general word for ear, so Tai tôi đau can refer to ear pain in a broad sense. It does not specify whether the pain is:

• outside the ear
• inside the ear
• around the ear area

If you need to be more specific, you would add extra words or explain further. But on its own, it simply communicates ear pain in a general way.