El líder escribió en el diario.

El is the masculine singular definite article, meaning the.

So:

• el líder = the leader

In Spanish, articles are used more often than in English, so a noun like líder normally needs one unless the context calls for something else.

The accent mark in líder shows where the stress goes:

• lí-der
• stress on the first syllable

Without the accent, standard Spanish spelling rules would suggest a different stress pattern, so the written accent is needed.

It also helps pronunciation for learners:

• líder sounds roughly like LEE-der, but with a Spanish d and a shorter vowel sound than in English.

No. Líder can refer to a man or a woman. The article changes:

• el líder = the male leader
• la líder = the female leader

So in this sentence, El líder tells you the leader is masculine.

Escribió is the preterite form of escribir for he/she/it wrote.

Here is the contrast:

• escribe = he/she writes or is writing (present)
• escribió = he/she wrote (completed past action)

So El líder escribió... means the writing happened in the past and is viewed as a finished action.

The accent mark shows that the stress falls on the last syllable:

• es-cri-bió

It also helps distinguish pronunciation and follows the spelling pattern of many preterite forms.

For example:

• escribi would be pronounced differently
• escribió clearly means he/she wrote

This is a very common pattern in the third person singular preterite of many -er and -ir verbs:

• comió
• vivió
• escribió

Yes, it absolutely could.

Spanish often drops subject pronouns and even noun subjects when the verb form already makes the subject clear enough from context. So both are possible:

• El líder escribió en el diario.
• Escribió en el diario.

Including El líder makes the subject explicit, which can be useful for:

• clarity
• emphasis
• introducing the person being talked about

En usually means in, on, or sometimes at, depending on context.

Here, escribió en el diario means wrote in the diary/journal/newspaper, depending on the intended meaning.

So en is the normal preposition used for writing in something.

Examples:

• escribió en el cuaderno = wrote in the notebook
• escribió en la revista = wrote in the magazine

Because Spanish usually needs an article here.

• el diario = the diary / the newspaper

English sometimes says in a diary or in the newspaper, and article usage does not match Spanish exactly. In Spanish, leaving out the article here would usually sound incomplete or unnatural.

So:

• en el diario is the normal form

Diario can mean different things depending on context, especially:

• diary / journal
• newspaper

In Spain, diario very often means newspaper. But it can also mean a diary/journal in the right context.

Since the meaning has already been shown to the learner, the important grammar point is that the Spanish word itself can have more than one possible meaning, and context decides which one is intended.

This is the most neutral and straightforward word order in Spanish:

• subject + verb + prepositional phrase

So:

• El líder = subject
• escribió = verb
• en el diario = where / in what he wrote

Spanish word order is more flexible than English, but this is the standard, natural order for a simple statement.

Yes. Spanish allows more flexibility than English.

For example:

• En el diario escribió el líder.
• Escribió el líder en el diario.

These are grammatically possible, but they may sound more marked, literary, or emphatic depending on context.

The original sentence,

• El líder escribió en el diario, is the most neutral and natural version for most situations.

The infinitive is escribir, meaning to write.

A quick breakdown:

• escribir = to write
• escribió = he/she wrote

So escribió is the third person singular preterite form of escribir.

A rough pronunciation guide is:

• El líder escribió en el diario
• el LEE-der es-kree-BYOH en el dya-ryo

A few useful pronunciation notes for Spain:

• líder: stress on the first syllable
• escribió: stress on the last syllable
• diario: usually pronounced as three syllables, roughly dia-rio

A more Spanish-like approximation would be:

• el LEE-ther es-kree-BYOH en el DYAH-ryo in many parts of Spain

That said, exact pronunciation varies by region.