Mama este ocupată acum, dar mă sună mai târziu.

Because ocupată agrees with Mama, which is feminine singular.

• ocupat = masculine singular
• ocupată = feminine singular

Since mama is feminine, the adjective must also be feminine:

• Tata este ocupat. = Dad is busy.
• Mama este ocupată. = Mom is busy.

Mamă is the basic dictionary form, meaning mother.

Mama is the definite form, roughly the mother, but in real usage it often simply means Mom or my mom, depending on context.

Romanian often uses the definite form for family members:

• mama = mom / the mother
• tata = dad / the father
• bunica = grandma / the grandmother

So Mama este ocupată acum is a natural way to say Mom is busy now.

In standard Romanian, you normally keep the verb a fi (to be) in sentences like this.

So:

• Mama este ocupată. = correct
• Romanian does not normally say the equivalent of Mom busy now in standard grammar.

That said, in everyday speech, este is often shortened to e:

• Mama e ocupată acum.

This is very common and natural.

The verb a suna can mean to call when talking about phoning someone.

In Romanian, to call someone uses a direct object, so me becomes mă, not îmi.

• mă sună = she calls me / she is calling me / she’ll call me
• mă = me as a direct object

Examples:

• Mă sună mama. = Mom is calling me.
• Te sun mâine. = I’ll call you tomorrow.

By contrast, îmi is usually an indirect object, like to me / for me, so it would not be the normal choice here.

Because short unstressed object pronouns in Romanian usually go before the conjugated verb.

So:

• mă sună = she calls me
• te sună = she calls you
• îl sună = she calls him

This is normal Romanian word order for clitic pronouns.

English says calls me, but Romanian usually says the equivalent of me calls.

Formally, sună is present tense.

However, Romanian often uses the present tense to talk about a future action when the time is clear from context. Here, mai târziu (later) makes the future meaning obvious.

So:

• mă sună mai târziu = literally she calls me later
• natural meaning: she’ll call me later

This is very common in Romanian.

If you want a more explicit future, you could also say:

• Mama mă va suna mai târziu.
• Mama o să mă sune mai târziu.

Because mai târziu means later, while târziu by itself usually means late.

Compare:

• Ne vedem mai târziu. = We’ll see each other later.
• Este târziu. = It is late.

So in your sentence:

• mă sună mai târziu = she’ll call me later

If you said only târziu, it would sound more like late, not simply later.

Acum means now.

In this sentence, it contrasts with mai târziu:

• acum = now
• mai târziu = later

So the sentence sets up a time contrast:

• now she is busy
• later she will call

Because dar means but, and in Romanian it is normally preceded by a comma when it joins two contrasting clauses.

So:

• Mama este ocupată acum, dar mă sună mai târziu.

This is standard punctuation.

The comma marks the contrast between:

• she is busy now
• she’ll call later

Yes, Romanian word order is fairly flexible, although some versions sound more natural than others.

The original sentence is very natural:

• Mama este ocupată acum, dar mă sună mai târziu.

You could also hear:

• Mama este acum ocupată, dar mă sună mai târziu.
• Mama este ocupată, dar mă sună mai târziu.

Or with a stronger focus on time:

• Acum mama este ocupată, dar mă sună mai târziu.

So the order can change for emphasis, but the original version is a very good neutral choice.

This sentence contains both:

• ă in ocupată, mă
• â in târziu

A simple learner-friendly guide:

• ă is a short neutral vowel, like the a in about, but shorter and clearer.
• â is a deeper central sound that English does not really have. It is the same sound as î in Romanian; the spelling just changes depending on position in the word.

So roughly:

• mă ≈ muh, but very short
• târziu begins with that special Romanian â sound

You do not need to perfect these immediately, but it is good to notice that ă and â are different vowels.

Yes. E is the short form of este, and it is extremely common in speech.

So both are correct:

• Mama este ocupată acum. = slightly more formal or careful
• Mama e ocupată acum. = more everyday and conversational

In normal conversation, many speakers would prefer e.

Yes, absolutely.

That version makes the future more explicit:

• o să mă sune = she is going to call me / she’ll call me

So you have at least three natural options:

• Mama este ocupată acum, dar mă sună mai târziu.
• Mama este ocupată acum, dar o să mă sune mai târziu.
• Mama este ocupată acum, dar mă va suna mai târziu.

Very roughly:

• mă sună mai târziu = natural, conversational future by context
• o să mă sune = very common spoken future
• mă va suna = more formal or written future