O să o sun pe mama mâine dimineață.

O să is a very common Romanian future marker. In everyday language, o să o sun means I will call her or I’m going to call her.

It is one of the most natural ways to make the future in spoken Romanian. Another future form is o voi suna pe mama, which sounds a bit more formal or written.

No.

• The first o is part of o să, the future marker.
• The second o is a short pronoun meaning her.

So in this sentence, the first o helps build the future, while the second o refers to mama.

This is a very common Romanian pattern called clitic doubling.

Romanian often uses:

• a short object pronoun, and
• the full noun

together, especially when the object is a specific person.

So o sun pe mama is literally something like I call her, my mother, but in Romanian this is normal and natural. English usually does not do this, but Romanian often does.

Because mama is a specific human direct object.

In Romanian, specific people used as direct objects are usually marked with pe.

Compare:

• Văd casa = I see the house
• O văd pe Maria = I see Maria
• O sun pe mama = I’m calling mom

So pe is not random here; it marks a definite person as the direct object.

With close family words, Romanian often leaves out the possessive if it is obvious from context.

So pe mama very naturally means my mother / mom here.

You can also say pe mama mea, but that is more explicit and can sound more emphatic.

Also, mama already contains the definite article -a, so it means the mother / mom, not just mother.

Romanian often drops subject pronouns because the verb form already shows who is doing the action.

Here, sun tells you the subject is I.

So O să o sun pe mama already means I will call mom.
You would add eu mainly for emphasis or contrast:

Eu o să o sun pe mama, nu tu.
= I’ll call mom, not you.

Sun comes from the verb a suna, meaning to call or to ring.

After o să, Romanian uses the subjunctive form of the verb. For a suna, that form happens to look the same as the present-tense sun.

That is why you get:

• sun = I call
• o să sun = I will call

With some other verbs, the form is more obviously different. For example:

• sunt = I am
• o să fiu = I will be

Yes, to a degree.

The basic order here is very natural:

O să o sun pe mama mâine dimineață.

But Romanian lets you move parts of the sentence for emphasis or style:

• Mâine dimineață o să o sun pe mama.
• Pe mama o să o sun mâine dimineață.

What usually does not change is the position of the clitic o: it normally stays right before the main verb sun.

Pe should stay. With a definite human direct object like mama, it is the standard choice.

The clitic o is also the most natural and safest choice here. Some speakers may omit such clitics in some contexts, but O să o sun pe mama is the normal form you should learn and use.

Yes. Mâine dimineață is a normal, everyday way to say tomorrow morning.

It usually means the morning period in general, not necessarily very early. You can place it at the end or at the beginning of the sentence:

• O să o sun pe mama mâine dimineață.
• Mâine dimineață o să o sun pe mama.

A quick guide:

• ă in să and -ță sounds like the a in sofa
• â in mâine has no exact English equivalent; it is a central Romanian vowel, roughly like a tight central uh
• ț in dimineață sounds like ts, as in cats

A couple of extra pronunciation notes:

• sun sounds roughly like soon
• dimineață is stressed on nea: di-mi-NEA-ță