Hay que descoser el pespunte.

Hay que + infinitive is an impersonal way to say that something needs to be done or must be done.

So Hay que descoser el pespunte means something like:

• The topstitching has to be unpicked
• We need to unpick the stitching
• It is necessary to undo the topstitching

It does not say exactly who has to do it. That is one of the main uses of hay que.

Because hay que does not name a person.

Compare:

• Hay que descoser el pespunte = It’s necessary to unpick the topstitching / We have to unpick it
• Tienes que descoser el pespunte = You have to unpick the topstitching
• Tengo que descoser el pespunte = I have to unpick the topstitching
• Tenemos que descoser el pespunte = We have to unpick the topstitching

So hay que is used when Spanish wants to express a general obligation without saying who exactly is responsible.

Because after hay que, Spanish uses an infinitive.

Pattern:

• hay que + infinitive

Examples:

• Hay que esperar = We have to wait
• Hay que coserlo = It has to be sewn
• Hay que descoser el pespunte = The topstitching has to be unpicked

So descoser stays in its base form, just like to unpick / to undo stitching in English.

Descoser means to unsew, to unstitch, or to unpick stitching.

It is built from:

• coser = to sew
• des- = a prefix that often gives the idea of undoing or reversing something

So:

• coser = sew
• descoser = undo sewing / unpick stitches

In sewing contexts, descoser is a very natural verb.

Pespunte is a sewing term. It usually refers to topstitching or a visible line of stitches.

In this sentence, el pespunte is the thing that needs to be undone.

The article el is there because Spanish normally uses the definite article with nouns like this when referring to a specific stitch line or seam already understood from the context.

So even if English might say simply undo the stitching, Spanish naturally says descoser el pespunte.

Because hay que is an impersonal structure.

There is no expressed subject such as yo, tú, or nosotros. Spanish is not saying who must do it, only that the action is necessary.

That is why you should think of hay que as a fixed expression meaning:

• one must
• you have to
• we need to
• it is necessary to

Which English translation sounds best depends on context.

In this structure, Spanish always uses hay que.

Even though hay comes from haber, you do not change it here to match a person:

• Hay que hacerlo
• not he que hacerlo
• not has que hacerlo
• not hemos que hacerlo

If you want to say I have to, you have to, etc., Spanish usually switches to tener que:

• Tengo que hacerlo
• Tienes que hacerlo
• Tenemos que hacerlo

So hay que is best learned as a set expression.

Yes. Very often, English translates hay que as we have to when the context is practical instructions or teamwork.

For example, in a sewing lesson, someone might say:

• Hay que descoser el pespunte y volver a coserlo.

A natural English translation could be:

• We need to unpick the topstitching and sew it again.

But grammatically, Spanish is still being impersonal. It does not literally say we.

Yes, those are possible, but they sound different in style.

• Hay que descoser el pespunte = very natural, common, straightforward
• Se tiene que descoser el pespunte = also possible, slightly heavier
• Debe descoserse el pespunte = more formal or technical

For everyday spoken instructions, hay que + infinitive is one of the most natural choices.

Normally, no: you would usually say el pespunte, not just pespunte.

Spanish often uses the definite article where English may sound more flexible. In a sewing context, el pespunte means the topstitching / the line of stitching that both speakers understand from the situation.

Without the article, the phrase would sound incomplete or unnatural in most normal contexts.

Yes, but the most neutral order is:

• Hay que descoser el pespunte.

You might sometimes hear variations for emphasis, such as:

• El pespunte hay que descoserlo.

That version puts el pespunte first for emphasis, and then repeats it with -lo. It is less neutral and more context-driven.

For a learner, the basic pattern to remember is:

• Hay que + infinitive + object

Yes, it has some irregularity because it comes from coser, which changes in some forms.

For example:

• coser → coso, coses, cose
• descoser → descoso, descoses, descose

But in your sentence, that does not matter much, because the verb is in the infinitive: descoser.

So you do not need a conjugated form here.

A simple pronunciation guide:

• Hay ≈ eye
• que ≈ keh
• descoser ≈ dess-koh-SER
• el ≈ el
• pespunte ≈ pess-POON-teh

In much of Spain, z and soft c have the th sound of think, but that does not affect this sentence, because there is no z or soft c here.

A rough full pronunciation:

• eye keh dess-koh-SER el pess-POON-teh

You can replace it with lo:

• Hay que descoserlo. = It has to be unpicked.

The pronoun is attached to the infinitive descoser, which is very common in Spanish.

So:

• descoser el pespunte
• descoserlo

This is useful because hay que + infinitive often appears with attached object pronouns:

• Hay que hacerlo
• Hay que coserlo
• Hay que descoserlo