Thưa bác sĩ, lưng tôi đau.

Thưa is a polite word used when addressing someone respectfully, especially in somewhat formal situations or when speaking to someone of higher status, older age, or professional authority.

In Thưa bác sĩ, it works a bit like:

• Excuse me, doctor
• Doctor,
• Respectfully, doctor

It does not carry the main meaning of the sentence. It sets the tone and shows politeness.

Because thưa + title/person is a common Vietnamese pattern for respectfully addressing someone.

So:

• Thưa bác sĩ = Doctor, ...
• Thưa cô = Teacher/Ma’am, ...
• Thưa ông = Sir, ...

In this sentence, bác sĩ is the person being addressed, not the subject of đau.

No. Vietnamese does not use articles like the and a/an the way English does.

So bác sĩ can simply mean:

• doctor
• the doctor
• a doctor

The exact meaning depends on context. In Thưa bác sĩ, it clearly means you are speaking directly to the doctor.

Both are possible, but they are structured differently.

1. Lưng tôi đau

Literally: My back hurts
This makes lưng tôi (my back) the topic/subject-like part, and đau describes its condition.

2. Tôi đau lưng

Literally: I have back pain / My back hurts
This is also very common in everyday speech.

So:

• Lưng tôi đau = slightly more like My back hurts
• Tôi đau lưng = slightly more like I have back pain / My back hurts

Both are natural. The version in your sentence focuses more directly on the back.

Because lưng tôi means my back.

In Vietnamese, possession is often shown by putting the possessor after the noun:

• lưng tôi = my back
• nhà tôi = my house
• mẹ tôi = my mother

So unlike English my back, Vietnamese commonly uses back + I/me.

It can behave a bit like both, depending on how you analyze Vietnamese grammar.

In beginner-friendly terms, đau means hurt / painful / ache and can describe a body part’s condition.

In lưng tôi đau:

• lưng tôi = my back
• đau = hurts / is painful

So you can think of đau here as meaning hurts or is painful.

This is common in Vietnamese: words often do not fit perfectly into English-style categories.

Because Vietnamese often does not need a copula like is/are in sentences describing states or qualities.

English:

• My back is painful
• My back hurts

Vietnamese:

• Lưng tôi đau

There is no need to insert a word equivalent to is here.

Yes, you could, and it would still be understandable.

But thưa makes it more polite and respectful, especially in a doctor-patient interaction.

Compare:

• Thưa bác sĩ, lưng tôi đau. = polite, respectful
• Bác sĩ, lưng tôi đau. = still understandable, but less formally polite

So if you want to sound courteous, thưa is a good choice.

Yes. Vietnamese pronouns depend heavily on relationship, age, and social context.

Tôi is a neutral, fairly safe way to say I. It is often used in formal or polite situations.

But depending on who is speaking, someone might also say:

• em if speaking respectfully to an older doctor
• cháu if the speaker is much younger
• con in certain family-like or traditional contexts

For example:

• Thưa bác sĩ, em đau lưng.
• Thưa bác sĩ, cháu đau lưng.

So tôi is correct, but not the only possibility.

Both can be natural, but they are slightly different in feel.

• lưng tôi đau = my back hurts
• tôi đau lưng = I have back pain / my back hurts
• tôi bị đau lưng = can sound more like I suffer from back pain or I’ve got back pain

The word bị is not always necessary here. In many everyday situations, learners should first get comfortable with:

• Tôi đau lưng.
• Lưng tôi đau.

These are simple and common.

A rough pronunciation guide:

• thưa ≈ thưa with the ưa vowel, somewhat like thw-uh but not exactly English
• bác = rising sharp tone
• sĩ = high, creaky/rising tone depending on dialect
• lưng ≈ luhng with the ư vowel
• tôi ≈ toy but not exactly English toy
• đau ≈ dow / dao

The tones are important:

• thưa — level-ish tone
• bác — sắc tone
• sĩ — ngã tone in Northern Vietnamese
• lưng — level tone
• tôi — level tone
• đau — level tone

If you are studying pronunciation, the hardest parts are usually:

• the vowel ư in thưa and lưng
• the difference between đ and English d
• the tones on bác and sĩ

It sounds polite and natural, especially in a respectful conversation with a doctor.

However, in very casual modern speech, many people might more naturally say:

• Bác sĩ ơi, tôi đau lưng.
• Bác sĩ, tôi đau lưng.

Still, Thưa bác sĩ, lưng tôi đau. is perfectly good Vietnamese and gives a respectful, careful impression.