La profesora divide la palabra en sílabas para que la pronunciación sea más clara.

Because Spanish often uses the definite article before a specific noun in a sentence like this. La profesora means you are talking about a particular teacher.

A useful contrast is:

• La profesora divide la palabra... = a specific teacher is doing the action
• Es profesora. = she is a teacher

With professions, Spanish usually drops the article after ser, but often keeps it when the person is the subject of the sentence.

Profesora is the feminine form, so it tells you the teacher is female.
The masculine form is profesor.

Examples:

• El profesor divide la palabra... = the male teacher...
• La profesora divide la palabra... = the female teacher...

In Spanish, many job titles change form depending on gender.

Divide is the third person singular present indicative of dividir.

So it matches la profesora:

• yo divido
• tú divides
• él/ella/usted divide

Here it means the teacher divides or is dividing in a general present-time sense.

Because the sentence is talking about one word being broken into syllables. Spanish uses the singular here for the same reason English does in the word.

If you wanted to talk about several words, you would say:

• La profesora divide las palabras en sílabas...

Because dividir una palabra en sílabas is the normal way to say divide a word into syllables.

Here, sílabas is being used in a general way, not referring to a specific set of already identified syllables. That is why no article is needed.

This is very common in Spanish after certain verbs:

• dividir en partes
• separar en grupos
• clasificar en categorías

Because para que introduces a whole clause with its own verb: la pronunciación sea más clara.

Compare:

• para + infinitive when there is no new finite verb
  
  • Estudio para aprender.
• para que + subjunctive when a new clause follows
  
  • Estudio para que mis notas mejoren.

In your sentence, the second part has its own verb, sea, so para que is needed.

Because para que normally triggers the subjunctive in Spanish.

The sentence expresses purpose: the teacher divides the word so that the pronunciation may be clearer. That kind of idea uses the subjunctive.

Sea is the present subjunctive of ser.

Compare:

• La profesora divide la palabra para que la pronunciación sea más clara.
  Purpose / intention
• La pronunciación es más clara.
  Simple statement of fact

Because clara is an adjective describing la pronunciación, which is a feminine singular noun.

So the adjective has to agree:

• la pronunciación clara
• la explicación clara
• el sonido claro

It is not claramente because that would be an adverb, and here Spanish is not describing how the teacher divides the word. It is describing the result: the pronunciation is clearer.

They show where the stress falls.

• sílabas: stress on the first syllable
• pronunciación: stress on the final -ón

This matters because Spanish spelling is closely tied to pronunciation. Without the accents, a reader might stress the words incorrectly.

Also, -ción is a very common ending in Spanish nouns, and it almost always carries a written accent.

Yes. Separar una palabra en sílabas is also very natural.

Both verbs work:

• dividir la palabra en sílabas
• separar la palabra en sílabas

A rough difference is:

• dividir = divide into parts
• separar = separate the parts from one another

In practice, both are common in a classroom or pronunciation context.

Yes. Spanish word order is fairly flexible.

For example, you could also say:

• Para que la pronunciación sea más clara, la profesora divide la palabra en sílabas.

That version puts the purpose first. The original sentence is more neutral and straightforward, but both are correct.

A rough Spain-Spanish pronunciation would be:

la pro-fe-SO-ra di-BI-de la pa-LA-bra en SI-la-bas PA-ra ke la პრო-nun-thia-THYON SE-a mas KLA-ra

A few useful points for Spain:

• ci in pronunciación is often pronounced like th in much of Spain
• z and soft c often sound like th in central/northern Spain
• h is silent, but there is no h in this sentence
• each vowel is pronounced clearly, so sea is two syllables: se-a

If you are learning a Spain accent, pronunciación is especially useful practice because it contains both clear vowels and the Spain-style ci sound.