Esta situación pide calma.

Because situación is a feminine singular noun, so the demonstrative has to match it:

• este = this, masculine singular
• esta = this, feminine singular

Since situación is feminine, you say esta situación.

A useful pattern:

• este problema
• esta idea
• este momento
• esta situación

In Spanish, many nouns ending in -ción are feminine, and situación follows that pattern.

Examples:

• la nación
• la solución
• la conversación
• la situación

So you would normally use:

• la situación
• esta situación
• una situación complicada

The accent mark shows where the stress goes: si-tua-CIÓN.

Without getting too technical, words ending in n, s, or a vowel are usually stressed on the second-to-last syllable unless there is an accent mark. The accent in situación tells you the stress is on the last syllable.

So the pronunciation is roughly:

• si-tua-CIÓN

Yes, pedir often means to ask for, but in Spanish it can also mean something more like:

• to call for
• to require
• to demand

So in Esta situación pide calma, pide does not mean the situation is literally speaking. It means the situation calls for calm or requires calm.

This is a very natural use of pedir in Spanish.

Yes. Spanish often lets non-human things be the subject of pedir when the meaning is to call for or to require.

So a sentence like this is normal:

• Esta situación pide calma.

It is similar in English to saying:

• This situation calls for calm.

Other similar Spanish examples:

• El momento pide prudencia.
• La ocasión pide una respuesta rápida.

Because calma is being used in a general, abstract sense here.

In Spanish, abstract nouns often appear without an article when talking about a quality in general:

• tener paciencia
• mostrar respeto
• pedir calma

If you said pide la calma, it would sound more specific, as if referring to a particular calmness already identified in context. In this sentence, the general idea is better: calm in general.

Here, calma is a noun.

It means something like:

• calm
• calmness

In this sentence, it is the thing being called for:

• pide calma = calls for calm

Compare:

• Necesitamos calma.
• Habla con calma.

In both cases, calma is a noun.

Because the subject is esta situación, which is third person singular.

The verb pedir changes like this in the present tense:

• yo pido
• tú pides
• él/ella/usted pide
• nosotros pedimos
• vosotros pedís
• ellos/ellas/ustedes piden

Since esta situación is like ella grammatically, the correct form is pide.

Because pedir is a stem-changing verb in the present tense.

It changes from e to i in most forms:

• pido
• pides
• pide
• pedimos
• pedís
• piden

So pide is irregular, but it follows the normal pattern for pedir.

Yes, it sounds natural and idiomatic. It is a fairly formal or neutral way to express that a situation requires a calm response.

It has a tone similar to:

• This situation calls for calm.

You might hear similar phrases in:

• news reports
• public statements
• formal conversation
• serious discussions

Yes. Requiere calma is also correct and natural.

There are slight nuance differences:

• pide calma = calls for calm, suggests the situation naturally demands it
• requiere calma = requires calm, slightly more direct or formal
• exige calma = demands calm, stronger and more forceful

So all three can work, but pide calma has a very idiomatic, elegant feel.

Yes, but Esta situación pide calma is the most straightforward and neutral order.

Spanish can move words around for emphasis, for example:

• Calma pide esta situación.
• Pide calma esta situación.

But these sound more marked or literary. For everyday use, the normal order is:

• Esta situación pide calma.

No. The personal a is used mainly before specific human direct objects.

Here:

• esta situación = subject
• calma = thing/abstract noun, not a person

So there is no reason to use the personal a.

Correct:

• Esta situación pide calma.

Not:

• Esta situación pide a calma.

In standard Spain Spanish, it would be roughly:

• EH-sta see-tua-THYON PEE-deh KAL-ma

A few useful notes:

• esta: stress on es
• situación: stress on the last syllable -ción
• In much of Spain, ci in situación sounds like thyon
• pide: two syllables, PI-de
• calma: stress on cal

Even if your accent is not from Spain, the sentence will still be understood perfectly if your pronunciation is clear.

Yes, depending on what you want to express.

For example:

• Esta situación pide paciencia.
• Esta situación pide prudencia.
• Esta situación pide una solución rápida.
• Esta situación pide atención.

The structure is very productive:

• [subject] + pide + [noun]

It is a useful pattern for saying that something calls for a certain response.