En el supuesto de que falle algo, pediremos ayuda.

En el supuesto de que is a more formal, legal, or carefully worded way to say if or in the event that.

• Si falla algo, pediremos ayuda. = more ordinary, everyday
• En el supuesto de que falle algo, pediremos ayuda. = more formal, more like in the event that something fails

So the sentence sounds more official or written than casual conversation.

Because en el supuesto de que triggers the subjunctive.

Spanish often uses the subjunctive after expressions that present something as hypothetical, possible, or not yet confirmed. Here, the failure has not happened; it is only being imagined as a possibility.

So:

• falla = present indicative
• falle = present subjunctive

After en el supuesto de que, Spanish normally uses the subjunctive:

• En el supuesto de que falle algo...

Falle is the present subjunctive, third person singular, of fallar.

The subject is algo, which is grammatically singular, so the verb is singular too:

• algo falle = something fails / should fail / were to fail

Quick breakdown:

• infinitive: fallar
• yo form: fallo
• present subjunctive stem: fall-
• third person singular subjunctive ending: -e
• result: falle

Pediremos is the simple future: we will ask for.

The sentence describes what will happen if that hypothetical situation occurs:

• If something fails, we will ask for help.

Why not the others?

• pedimos = present tense, we ask / we are asking
• pediríamos = conditional, we would ask

Here, Spanish is stating a future result of a possible condition, so pediremos fits very naturally.

Also, a common pattern is:

• hypothetical condition + future result
  En el supuesto de que falle algo, pediremos ayuda.

Yes. A very natural version would be:

• Si falla algo, pediremos ayuda.

That is more common in everyday speech. But notice the mood change:

• si falla algo → normally uses the indicative
• en el supuesto de que falle algo → uses the subjunctive

So both are possible, but they are not structured the same way.

Algo means something.

It is much more common and natural than alguna cosa in a sentence like this.

• algo = standard, concise, natural
• alguna cosa = possible, but usually less elegant here

So:

• si falla algo = if something fails sounds much better than
• si falla alguna cosa

Here, fallar usually means something like:

• to fail
• to stop working
• to go wrong
• to malfunction

Its exact meaning depends on context.

For example:

• Falló el motor. = The engine failed / stopped working.
• Algo falló. = Something went wrong.

So in this sentence, falle algo suggests that something might go wrong or some component/system might fail.

Because the full expression is en el supuesto de que.

You should learn it as a chunk:

• en el supuesto de que = on the assumption that / in the event that

The de belongs to the noun phrase el supuesto de...
Just like:

• la posibilidad de que...
• el hecho de que...

So this is not an extra or optional de. It is part of the structure.

It is definitely formal and more likely to appear in:

• instructions
• policies
• technical writing
• business communication
• legal or administrative language

In everyday conversation, many speakers in Latin America would say something simpler, such as:

• Si falla algo, pedimos ayuda.
• Si llega a fallar algo, pediremos ayuda.
• Si algo falla, pediremos ayuda.

So the original sentence is grammatical and natural, but it sounds more careful and formal than casual speech.

Yes. Both are possible:

• Si falla algo...
• Si algo falla...

The difference is mostly one of style and focus.

• Si falla algo can sound a bit more natural when introducing an unknown problem: if something fails / if anything goes wrong
• Si algo falla puts algo slightly more upfront

In the original sentence, falle algo sounds quite natural because Spanish often places the verb before an indefinite subject like algo.

Yes, and in many contexts that would sound more common.

• En caso de que falle algo, pediremos ayuda.

This also means in case / in the event that something fails and also takes the subjunctive.

Comparison:

• en el supuesto de que = more formal, more like under the assumption that
• en caso de que = still formal-neutral, but more common and practical

Because after en el supuesto de que, Spanish wants the subjunctive, not the indicative.

So the contrast is:

• Si falla algo... → indicative
• En el supuesto de que falle algo... → subjunctive

The subject being algo does not matter for the mood choice; the triggering phrase does.

Here ayuda means help/assistance in a general, uncountable sense.

• pedir ayuda = to ask for help

This is a very common collocation in Spanish. You usually do not need an article:

• pediremos ayuda not usually
• pediremos una ayuda

Using una ayuda would usually change the meaning and sound more specific, depending on context.

Not really in natural English. Even though en el supuesto de que is literally close to under the assumption that, the natural English meaning here is more like:

• If something fails, we’ll ask for help.
• In the event that something fails, we’ll ask for help.

Also, the subjunctive falle does not mean should fail word-for-word every time. It simply marks the event as hypothetical or unconfirmed. English usually does not show that with a special verb form in the same way.

Yes: two very useful chunks.

1. en el supuesto de que + subjunctive
   Use this for formal hypothetical situations.

2. pedir ayuda
   A very common way to say to ask for help.

If you remember those as complete patterns, the sentence becomes much easier to understand and reuse.