Mi abuelo habla del pasado.

Del is the standard contraction of de + el.

• de = of / about / from
• el = the
• de el pasado becomes del pasado

So:

• habla del pasado = he talks about the past

This contraction is required in normal Spanish when de is followed by the masculine singular article el.

A useful comparison:

• de + el → del
• a + el → al

But do not contract if El is part of a proper name:

• de El Escorial → not del Escorial if the official name is El Escorial

In Spanish, possessive words like mi, tu, su, nuestro usually go directly before the noun, without an article.

So you say:

• mi abuelo = my grandfather
• tu casa = your house

Not:

• el mi abuelo

This is different from older forms of Spanish and from some other languages. In modern standard Spanish, mi abuelo is the normal structure.

Habla is the third person singular form of the verb hablar in the present tense.

The subject is mi abuelo, which means my grandfather, so the verb has to match he:

• yo hablo = I speak / I talk
• tú hablas = you speak / you talk
• él/ella habla = he/she speaks / talks

So:

• Mi abuelo habla = My grandfather talks / speaks

The Spanish present tense often covers both the simple present and, depending on context, sometimes an idea close to the English present progressive.

So habla can mean:

• talks
• is talking

depending on the situation.

Without more context, Mi abuelo habla del pasado is usually understood as a general statement:

• My grandfather talks about the past
• or My grandfather talks about the past a lot

If you specifically want is talking right now, Spanish often uses:

• Mi abuelo está hablando del pasado

But the simple present is still very common in many situations.

Spanish often uses the definite article where English might not.

Here, el pasado means the past as a general concept.

So:

• hablar del pasado = to talk about the past

Using the article sounds natural in Spanish. Saying just habla de pasado would not sound correct here.

This is very common with abstract nouns:

• el amor = love
• la historia = history
• el futuro = the future
• el pasado = the past

Here, pasado is a noun meaning the past.

It can also be an adjective in other contexts:

• el año pasado = last year
• tiempo pasado = past time

But in del pasado, it is clearly being used as a noun:

• the past
• things that happened before now
• earlier times, memories, history, former experiences

Yes, you can. Hablar de and hablar sobre can both mean to talk about.

• hablar de algo = the most common, everyday way to say talk about something
• hablar sobre algo = also correct, sometimes slightly more formal or more like speak on the subject of

So both are fine:

• Mi abuelo habla del pasado
• Mi abuelo habla sobre el pasado

In ordinary conversation, hablar de is usually the most natural choice.

In Spain Spanish, abuelo is pronounced approximately ah-BWE-lo.

A rough breakdown:

• a as in father
• bue like bwe
• lo like loh

The stress is on the second syllable:

• a-BUE-lo

A few pronunciation notes:

• b in Spanish is softer than English b in many positions
• ue forms a combined sound, like bwe
• the l is a clear Spanish l

Abuelo literally means grandfather, but depending on tone and context it can also correspond to grandpa.

• mi abuelo = my grandfather / my grandpa

Spanish does not always separate formal and informal family words the same way English does. Tone matters a lot.

If you want a more affectionate or familiar word, people may also say:

• abuelito = grandpa / dear grandpa / little grandpa

That ending -ito often adds affection.

Spanish often leaves out subject pronouns because the verb ending already tells you who the subject is.

Here, habla already shows he/she/you formal singular, and the noun mi abuelo makes it completely clear who the subject is.

So Spanish normally says:

• Mi abuelo habla del pasado

You could say:

• Mi abuelo, él habla del pasado

but that usually sounds unnecessary or emphatic in this context.

This is one of the big differences from English: Spanish is often a pro-drop language, meaning pronouns can be omitted when the meaning is clear.

Yes. Hablar can correspond to both to speak and to talk in English.

Examples:

• Hablo español. = I speak Spanish.
• Hablo con mi amigo. = I talk with my friend.
• Hablamos del pasado. = We talk about the past.

In your sentence, talk about is the most natural translation:

• Mi abuelo habla del pasado. = My grandfather talks about the past.

Yes. Both the noun and the verb would change.

• Mi abuelo habla del pasado. = My grandfather talks about the past.
• Mis abuelos hablan del pasado. = My grandparents talk about the past.

Changes:

• mi → mis for plural
• abuelo → abuelos
• habla → hablan

This is a good reminder that Spanish verbs must agree with the subject.