Mi padre mide la pared antes de colgar el cuadro.

Mide is the third-person singular present tense form of medir (to measure).

So:

• yo mido
• tú mides
• él/ella/usted mide
• nosotros/nosotras medimos
• vosotros/vosotras medís
• ellos/ellas/ustedes miden

This verb is stem-changing: the e in the stem changes to i in most present-tense forms.

So:

• medir → mide
• but nosotros medimos, vosotros medís stay without the change

That is why the sentence uses mide for mi padre.

In Spanish, a possessive adjective like mi, tu, su, nuestro usually goes directly before the noun and normally does not take an article.

So you say:

• mi padre = my father
• mi casa = my house

Not:

• el mi padre ✘

Spanish does have other possessive structures, such as el padre mío, but that is less neutral here and often adds emphasis or sounds more marked. The normal everyday way is mi padre.

Spanish uses definite articles (el, la, los, las) much more often than English does.

Here, la pared means the wall, referring to the wall being measured. Even if English might sometimes sound more natural with a wall depending on context, Spanish commonly uses the article with specific concrete nouns in situations like this.

So mide la pared is the natural way to say measures the wall.

Because la pared is a thing, not a person.

Spanish uses the personal a before a specific human being (and sometimes pets or personified beings) when that noun is a direct object.

Examples:

• Veo a mi padre = I see my father
• Veo la pared = I see the wall

In your sentence, la pared is the direct object of mide, but it is not a person, so there is no personal a.

Because after antes meaning before, Spanish normally uses de when it is followed by an infinitive.

So the pattern is:

• antes de + infinitive

Examples:

• antes de salir = before leaving
• antes de comer = before eating
• antes de colgar el cuadro = before hanging the picture

So antes colgar would be incorrect here.

It is in the infinitive because it comes after the preposition de in the structure antes de + infinitive.

This structure is used when the action is expressed in a general way, often when the subject is the same as the main clause or when the subject does not need to be stated again.

So:

• Mi padre mide la pared antes de colgar el cuadro.

This works like:

• My father measures the wall before hanging the picture.

If Spanish wanted to use a full clause with a different or explicit subject, it would usually use:

• antes de que + subjunctive

For example:

• Mi padre mide la pared antes de que yo cuelgue el cuadro.
• My father measures the wall before I hang the picture.

Yes. Colgar is also a stem-changing verb in the present tense: o → ue.

Present tense:

• cuelgo
• cuelgas
• cuelga
• colgamos
• colgáis
• cuelgan

In your sentence, though, it appears as the infinitive: colgar, so you do not see the stem change there.

Also, in other tenses it may behave differently depending on the form. So it is a good verb to learn as slightly irregular.

Here, cuadro most naturally means picture, painting, or framed picture.

In Spain, colgar un cuadro is a very normal expression for hanging a picture/painting on the wall.

Depending on context, cuadro can mean different things, such as:

• a painting
• a framed picture
• a picture on the wall
• sometimes other meanings in different contexts

But in this sentence, because of la pared and colgar, the meaning is clearly something like a picture/painting.

Using el cuadro suggests that the speaker has a specific picture in mind, one that is already known from the context.

So:

• el cuadro = the picture / the painting
• un cuadro = a picture / a painting

Both are grammatically possible, but they mean slightly different things.

Compare:

• Mi padre mide la pared antes de colgar el cuadro.
  He is talking about a particular picture.

• Mi padre mide la pared antes de colgar un cuadro.
  He is talking about hanging some picture, not necessarily one already identified.

Yes, absolutely.

• Mi padre mide la pared antes de colgar el cuadro.
• Antes de colgar el cuadro, mi padre mide la pared.

Both are correct and mean essentially the same thing.

The difference is mostly one of word order and emphasis:

• starting with Mi padre puts the focus first on who is doing the action
• starting with Antes de colgar el cuadro highlights the time/sequencing first

Spanish is often more flexible with word order than English, as long as the sentence remains clear.

Spanish often uses the simple present for ordinary statements, routines, or to describe an action in a straightforward way.

So:

• Mi padre mide la pared... = My father measures / is measuring the wall...

In many contexts, Spanish prefers the simple present where English might use either measures or is measuring, depending on context.

If you say:

• Mi padre está midiendo la pared antes de colgar el cuadro,

that specifically emphasizes that the action is in progress right now. It is possible, but it sounds more marked and less neutral than the original sentence.

So the simple present is the most natural default here.

In this sentence, the most natural interpretation is that the same person—my father—is both:

• measuring the wall
• hanging the picture

That is because antes de + infinitive often implies the same subject unless context tells you otherwise.

So Spanish listeners will normally understand:

• My father measures the wall before hanging the picture himself.

If you want to make it clear that someone else is doing the hanging, Spanish usually switches to a full clause:

• Mi padre mide la pared antes de que mi hermana cuelgue el cuadro.
• My father measures the wall before my sister hangs the picture.

Pared is pronounced roughly pa-RED, with the stress on the last syllable.

It is feminine, so it takes:

• la pared
• una pared

There is no special reason you can always predict from meaning alone; noun gender in Spanish often just has to be learned with the word. A good habit is to memorize nouns together with their article:

• la pared
• el cuadro

That helps you remember gender naturally.