כשהמרצה מסבירה לאט, אני מבין טוב יותר.

כש־ is a short form of כאשר and means when.

In Hebrew, this כש־ is usually attached directly to the following word, so:

• כשהמרצה = when the lecturer...

This is very common in everyday Hebrew.
A more formal version would be:

• כאשר המרצה מסבירה לאט, אני מבין טוב יותר.

Both are correct, but כש־ sounds more natural in spoken Hebrew.

The ה־ is the Hebrew definite article, meaning the.

So:

• מרצה = lecturer / instructor
• המרצה = the lecturer

In Hebrew, the is not a separate word like in English. It is added to the beginning of the noun.

Because המרצה here is understood as feminine.

Hebrew present-tense verbs agree with the subject in gender and number. So:

• מרצה מסביר = a male lecturer explains
• מרצה מסבירה = a female lecturer explains

Even though מרצה can refer to either a man or a woman, the verb form tells you which one is meant here.

No. That is an important point.

Even though מרצה ends in ־ה, it is a noun that can refer to either:

• a male lecturer
• a female lecturer

The ending does not automatically make it feminine.
You have to look at agreement in the sentence:

• המרצה מסביר → male lecturer
• המרצה מסבירה → female lecturer

So in this sentence, the verb מסבירה is what tells you the lecturer is female.

In Hebrew present-tense sentences, the verb to be is usually not expressed.

English says:

• the lecturer is explaining
• I am understanding

Hebrew simply says:

• המרצה מסבירה
• אני מבין

This is normal Hebrew grammar.
There is no present-tense form of to be used in ordinary sentences like this.

מבין is the masculine singular form.

So this sentence, as written, is being said by a male speaker:

• אני מבין = I understand / I understand better

If the speaker is female, it would be:

• אני מבינה טוב יותר

So yes, a woman could say the sentence, but she would normally use מבינה instead of מבין.

לאט means slowly, so here it functions as an adverb.

It describes how the lecturer explains:

• מסבירה לאט = explains slowly

Unlike adjectives, adverbs in Hebrew usually do not change for gender or number. So לאט stays the same regardless of who is doing the action.

Hebrew often forms comparisons with יותר, which means more.

So:

• טוב = good / well
• טוב יותר = better / more well

In this sentence, טוב יותר means better in the sense of I understand better.

This is very natural Hebrew. You may also hear:

• יותר טוב

Both are common in speech, though טוב יותר may sound a bit neater or more standard in some contexts.

Hebrew often uses טוב where English would use either good or well.

So:

• אני מבין טוב literally looks like I understand good
• but idiomatically it means I understand well

This is normal Hebrew usage. English separates good and well more strictly than Hebrew does in many everyday sentences.

Yes. Hebrew allows some flexibility.

The sentence can also be written as:

• אני מבין טוב יותר כשהמרצה מסבירה לאט.

This means the same thing.

The version with the כש־ clause first puts a little more focus on the condition or circumstance:

• When the lecturer explains slowly, I understand better.

The version with אני מבין first starts with the main point:

• I understand better when the lecturer explains slowly.

Both are natural.

Because the sentence begins with a subordinate clause:

• כשהמרצה מסבירה לאט = when the lecturer explains slowly

Then comes the main clause:

• אני מבין טוב יותר = I understand better

In Hebrew, when a subordinate clause comes first, it is very common to separate it from the main clause with a comma. This is similar to English:

• When the lecturer explains slowly, I understand better.

Usually no. In this sentence, כש־ means when.

Hebrew distinguishes between:

• כש־ / כאשר = when
• אם = if

So:

• כשהמרצה מסבירה לאט... = when the lecturer explains slowly...
• אם המרצה מסבירה לאט... would mean if the lecturer explains slowly...

That changes the meaning from a general time/circumstance to a condition.

Only the verb in the first clause would change:

• כשהמרצה מסביר לאט, אני מבין טוב יותר.

If the speaker is still male, מבין stays the same.

If the speaker is female, then it would be:

• כשהמרצה מסביר לאט, אני מבינה טוב יותר.

So Hebrew keeps track of gender in these present-tense forms.

Yes. In Hebrew, the present tense is built from forms that are historically participles, but in modern Hebrew they function as ordinary present-tense verb forms.

So מסבירה can be understood grammatically as the present-tense form meaning:

• explains
• is explaining

Likewise:

• מבין = understands / is understanding

Hebrew present tense does not usually distinguish between simple present and present progressive the way English does. Context tells you which English translation fits best.