כשהמורה מתחילה לדבר, אני מפסיק לשמוע מוזיקה.

כשהמורה means when the teacher.

It is made of:

• כש־ = when
• המורה = the teacher

In Hebrew, short connecting words like כש־ are often attached directly to the following word. So instead of writing them separately, Hebrew commonly writes:

• כשהמורה = when the teacher

A more formal alternative is כאשר המורה.

Because המורה already tells you who is doing the action: the teacher.

Hebrew does not need to add a separate subject pronoun if the subject is already stated. So:

• המורה מתחילה = the teacher begins / the teacher is beginning

Adding היא would usually be unnecessary here.

Because המורה here refers to a female teacher, so the verb form agrees with her gender.

In Hebrew present tense, verbs behave a lot like adjectives and must match the subject in:

• gender
• number

So:

• המורה מתחילה = the teacher begins/is beginning (female)
• המורה מתחיל = the teacher begins/is beginning (male)

Even though מורה can mean either male teacher or female teacher, the verb tells you which one is meant here.

In Hebrew, first-person present tense forms often show the speaker’s gender.

So:

• אני מפסיק = I stop / I am stopping said by a male
• אני מפסיקה = I stop / I am stopping said by a female

English does not mark this, but Hebrew does.

Hebrew present tense is often used for:

• general truths
• repeated situations
• habitual actions
• actions happening in a typical scenario

So this sentence means something like:

• Whenever the teacher starts speaking, I stop listening to music or
• When the teacher starts speaking, I stop listening to music

This is a normal use of Hebrew present tense.

The ל־ here marks the infinitive, like English to.

So:

• לדבר = to speak
• לשמוע = to hear / to listen

After verbs like:

• מתחיל = begins
• מפסיק = stops

Hebrew commonly uses an infinitive:

• מתחילה לדבר = begins to speak / starts speaking
• מפסיק לשמוע = stops hearing / stops listening

Literally, לשמוע means to hear. But in everyday Hebrew, לשמוע מוזיקה very often means to listen to music.

So this sentence is natural.

There is also:

• להקשיב למוזיקה = to listen to music

The difference is roughly:

• לשמוע מוזיקה = hear/listen to music in a general sense
• להקשיב למוזיקה = listen attentively to the music

In this sentence, לשמוע מוזיקה is completely normal.

Because מוזיקה is the direct object of לשמוע.

So:

• לשמוע מוזיקה = to hear/listen to music

No extra preposition is needed.

But with להקשיב, Hebrew does use a preposition:

• להקשיב למוזיקה = to listen to music

So the two verbs behave differently:

• לשמוע מוזיקה
• להקשיב למוזיקה

• לדבר = to speak
• להתחיל לדבר = to start speaking / to begin to speak

So:

• כשהמורה מדברת = when the teacher is speaking
• כשהמורה מתחילה לדבר = when the teacher starts speaking

The sentence focuses on the moment the teacher begins speaking, not just the fact that she is speaking.

Yes. Hebrew word order is fairly flexible.

This sentence:

• כשהמורה מתחילה לדבר, אני מפסיק לשמוע מוזיקה.

could also be:

• אני מפסיק לשמוע מוזיקה כשהמורה מתחילה לדבר.

Both are natural. The version with כשהמורה מתחילה לדבר first puts more emphasis on the time condition: when the teacher starts speaking.

The comma is natural here because the sentence begins with a subordinate clause:

• כשהמורה מתחילה לדבר = when the teacher starts speaking

Then comes the main clause:

• אני מפסיק לשמוע מוזיקה = I stop listening to music

In careful writing, the comma is very common and helpful. In informal writing, some people may omit punctuation, but the comma is a good choice here.

Yes.

• כש = when
• כאשר = when

So you could say:

• כאשר המורה מתחילה לדבר, אני מפסיק לשמוע מוזיקה.

The meaning is the same, but כאשר sounds more formal or literary. כש is more common in everyday speech and writing.

Their dictionary forms are:

• מתחילה ← להתחיל = to begin, to start
• מפסיק ← להפסיק = to stop, to cease

In the sentence, they appear in present-tense forms that agree with the subject:

• מתחילה = feminine singular present
• מפסיק = masculine singular present

So if you look them up in a dictionary, search for:

• להתחיל
• להפסיק