Cháu ở nhà với bà.

Both, depending on context.

In Vietnamese, family words are often used as pronouns. Cháu can mean:

• grandchild
• nephew / niece
• I / me, when the speaker is younger than the person they are talking to and wants to speak respectfully

In Cháu ở nhà với bà, cháu is the subject of the sentence. It very often means I if the speaker is talking to an older person, especially a grandparent.

So this word is not just vocabulary; it also shows the relationship between the speaker and the other person.

Vietnamese often leaves out words like my, your, and the when the relationship is already clear from context.

Here, cháu and bà naturally go together as a family relationship:

• cháu = grandchild
• bà = grandmother

So bà can easily be understood as my grandmother without saying a separate word for my.

This is very normal in Vietnamese. Kinship terms do a lot of work that English usually handles with pronouns and possessives.

Ở here means something like:

• to be at
• to stay at
• to live at, depending on context

In this sentence, it is best understood as be at home or stay at home.

Important point: ở is not the general English verb to be. It is specifically used for location or residence.

Examples:

• Cháu ở nhà = I am at home
• Cháu ở Hà Nội = I live in Hanoi / I am in Hanoi

So ở connects the subject to a place.

It can mean any of those, depending on context.

Ở nhà is a very common expression and usually means:

• to be at home
• to stay home

In some contexts it can also mean to live at home, but that usually becomes clear from the situation.

Without extra time words, Cháu ở nhà với bà is neutral and could mean:

• I am at home with Grandma
• I stay at home with Grandma

If Vietnamese wants to be more specific, it often adds time or aspect words:

• đang for an action in progress
• đã for past
• sẽ for future

It can mean both.

• nhà = house
• nhà = home

In ở nhà, English usually translates it more naturally as at home, not at the house.

So although nhà literally refers to a house/home, the whole phrase ở nhà works like a set expression meaning to be at home.

Với means with here.

It shows accompaniment, so với bà means with Grandma.

So the structure is:

• Cháu = subject
• ở nhà = be at home
• với bà = with Grandma

Together: Cháu ở nhà với bà = I am at home with Grandma.

Not if you want to keep the meaning with Grandma.

Compare:

• Cháu ở nhà = I am at home
• Cháu ở nhà với bà = I am at home with Grandma

So với is necessary to show that Grandma is accompanying the subject.

Both are possible, but they suggest slightly different structures.

Cháu ở nhà với bà

• main subject = cháu
• bà is the accompanying person
• natural meaning: I am at home with Grandma

Cháu với bà ở nhà

• cháu với bà acts more like a combined subject
• meaning: Grandma and I are at home

So the original sentence focuses more on cháu as the subject, while bà is added with with.

Vietnamese does not mark tense the way English does.

A sentence like Cháu ở nhà với bà is tense-neutral by itself. In many situations, it will be understood as present:

• I am at home with Grandma

But depending on context, it could also refer to another time.

Vietnamese usually makes time clear with:

• context
• time expressions such as hôm nay, bây giờ, hôm qua, ngày mai
• aspect markers such as đã, đang, sẽ

Examples:

• Cháu đang ở nhà với bà = I am currently at home with Grandma
• Cháu đã ở nhà với bà = I was at home with Grandma
• Cháu sẽ ở nhà với bà = I will be at home with Grandma

Not always, but that is the most likely meaning here.

Bà can mean:

• grandmother
• an older woman
• a respectful way to address or refer to an elderly woman

In this sentence, because the subject is cháu, the family meaning grandmother is the most natural interpretation.

So while bà has more than one possible use, here it strongly suggests a grandparent relationship.

A rough pronunciation guide:

• cháu: roughly like chow, with a rising tone
• ở: a short vowel somewhat like uh/er, with a dipping-rising tone
• nhà: roughly nya, with a low falling tone
• với: roughly vuhy or vwuhy, with a rising tone
• bà: roughly bah, with a low falling tone

A few important notes:

• nh in nhà is pronounced like the ny sound in canyon
• tones matter a lot in Vietnamese
• the accent marks are part of the spelling, not optional decoration

If you ignore the tones, people may misunderstand you or need extra context to figure out what you mean.