La meva mare i jo anirem juntes al teatre divendres.

In Catalan, possessives normally go together with the definite article. So la meva mare is the standard pattern, not just meva mare.

A few examples:

• la meva mare
• el meu pare
• les meves germanes

This is different from English, where my mother has no article. For a learner, using article + possessive + noun is the safest rule.

Catalan does often omit subject pronouns, because the verb ending already tells you the person. But here the speaker wants to name the two people explicitly: my mother and I. For that, jo must appear.

So:

• La meva mare i jo anirem... = correct

Also, after i in a subject, standard Catalan uses jo, not mi.

Compare:

• la meva mare i jo = subject
• amb mi = after a preposition

So mi is used after prepositions, but jo is used as a subject.

Anirem is the 1st person plural future of anar (to go). It means we will go.

The future forms are:

• aniré
• aniràs
• anirà
• anirem
• anireu
• aniran

This verb is a little irregular, because the future uses anir-.

If you said anem, that would be present tense: we go or we are going. In conversation, the present can sometimes refer to the near future, but anirem is the clear future form.

Because juntes agrees with the people in the subject.

Here the subject is la meva mare i jo. If both people are female, Catalan uses the feminine plural form:

• juntes

If one of the people were male, the usual form would be:

• junts

So:

• woman + woman → juntes
• man + woman → junts

This is something English does not do, because together does not change form. In Catalan, junt/junta/junts/juntes behaves like an adjective and agrees in gender and number.

You can leave it out.

La meva mare i jo anirem al teatre divendres is already a complete, natural sentence.

Adding juntes simply makes the idea of together explicit. It adds emphasis, as if you are highlighting that the two of you are going as a pair.

Al is a contraction of a + el.

So:

• a + el teatre → al teatre

After anar, Catalan normally uses a to show destination:

• anar al teatre
• anar al cinema
• anar a casa
• anar a l'escola

So al teatre means to the theatre / theater.

This is also why you do not say en el teatre here. En el teatre would mean in the theater, not to the theater.

Catalan usually does not need a preposition before days of the week in this kind of sentence.

So:

• divendres = on Friday / Friday

That is completely normal Catalan.

A useful contrast:

• divendres = Friday / on Friday
• els divendres = on Fridays / every Friday

In this sentence, divendres most naturally refers to a specific upcoming Friday.

Yes, you could. Both are grammatically possible.

• Jo i la meva mare anirem...
• La meva mare i jo anirem...

However, putting yourself second often sounds more natural or polite, much like in English with my mother and I rather than I and my mother.

So La meva mare i jo is a very natural choice.

Yes. Catalan word order is fairly flexible.

For example, you could also say:

• Divendres la meva mare i jo anirem juntes al teatre.
• La meva mare i jo anirem al teatre divendres.

These are still natural. The difference is mostly about emphasis:

• putting divendres first highlights the time
• putting it at the end is more neutral

The version you were given is a very normal, natural order.