Hablé con mi ex ayer.

Because hablé is the preterite, which is used for a completed action at a specific time in the past.

• Hablé con mi ex ayer = I spoke / talked to my ex yesterday.
• Hablaba con mi ex would usually mean I was talking to my ex or I used to talk to my ex, depending on context.

Since ayer gives a clear finished time, hablé is the natural choice.

The accent mark shows where the stress goes: ha-BLÉ.

It is also part of the correct spelling of the first-person singular preterite of hablar:

• yo hablé
• tú hablaste
• él/ella habló

Without the accent, hable would be a different form, such as the present subjunctive: Espero que yo hable.

Spanish often leaves out subject pronouns because the verb ending already shows who is doing the action.

• Hablé already means I spoke
• So yo is not necessary

You can say Yo hablé con mi ex ayer, but it usually adds emphasis, contrast, or clarity.

For example:

• Yo hablé con mi ex ayer, no mi hermana.
  = I spoke to my ex yesterday, not my sister.

Because the verb hablar commonly uses con when you mean to talk with / to someone.

• Hablar con alguien = to talk to/with someone

Examples:

• Hablé con Ana
• ¿Has hablado con tu jefe?

You may also see hablar de for to talk about:

• Hablamos de política = We talked about politics

So:

• hablar con = talk to/with
• hablar de = talk about

Because mi ex is the object of the preposition con, not the direct object of the verb.

The personal a appears before a direct object that is a person:

• Vi a mi ex ayer = I saw my ex yesterday

But here you have:

• Hablé con mi ex ayer

The structure is already con + person, so no extra a is needed.

Yes. Mi ex can refer to either one, and it often depends on context.

That is because ex itself does not change form:

• mi ex
• tu ex
• su ex

If you want to be more specific, you can say:

• mi exnovio = my ex-boyfriend
• mi exnovia = my ex-girlfriend

In everyday speech, mi ex is very common and natural.

In everyday modern Spanish, yes, ex is very commonly used as a noun to mean ex-partner or former partner.

Examples:

• Mi ex vive en Madrid
• Nunca hablo con mis ex

It can also work as a prefix in words like:

• exnovio
• exmarido
• expareja

So in this sentence, mi ex is perfectly normal Spanish.

Yes. Spanish word order is flexible, and ayer can move around.

All of these are possible:

• Hablé con mi ex ayer
• Ayer hablé con mi ex
• Hablé ayer con mi ex

The most neutral and common options are probably:

• Hablé con mi ex ayer
• Ayer hablé con mi ex

The meaning stays basically the same, but the focus can shift slightly depending on placement.

Normally, no. With ayer, Spanish usually uses the preterite, not the present perfect.

So the natural sentence is:

• Hablé con mi ex ayer

In Spain, the present perfect (he hablado) is often used for recent past connected to the present, especially with time expressions like:

• hoy
• esta mañana
• esta semana

For example:

• Hoy he hablado con mi ex

But with ayer, hablé is the standard choice.

Either is fine in English.

• Hablé con mi ex ayer can mean I spoke to my ex yesterday
• It can also mean I talked to my ex yesterday

Spanish hablar con covers both ideas very naturally.

A simple pronunciation guide would be:

ah-BLEH kon mee eks ah-YER

A few key points:

• h is silent in Spanish: hablé starts like a-
• hablé is stressed on the last syllable because of the accent
• ex is usually pronounced like eks
• ayer in Spain is roughly ah-YER

A more natural connected pronunciation may sound a bit like: ah-BLEH kom-mi-eks ah-YER

Yes, completely natural.

A speaker from Spain would easily say:

• Hablé con mi ex ayer

It is short, idiomatic, and very normal everyday Spanish.

Yes. If the person is already clear from context, you could say:

• Hablé con él ayer
• Hablé con ella ayer

You would still keep con, because hablar con alguien requires it.

You would not replace it with a direct object pronoun like lo or la in this structure. So:

• Hablé con él/ella = correct
• Lo hablé = incorrect for this meaning

It is the first-person singular preterite indicative of hablar.

Breakdown:

• verb: hablar
• tense: pretérito perfecto simple / preterite
• person: yo

So:

• yo hablé = I spoke / I talked

This tense is used for completed past events.