אם השיעור מתחיל בחמש וחצי, אני אבוא מוקדם.

אם means if.

It introduces a condition, just like if in English:

• אם השיעור מתחיל... = If the lesson starts...

Very often, אם is the basic word you will use for if in Hebrew.

The ה at the beginning is the definite article, meaning the.

So:

• שיעור = a lesson / lesson
• השיעור = the lesson

Hebrew attaches the directly to the noun, instead of writing it as a separate word.

This is very similar to English.

In English, we say:

• If the lesson starts at 5:30, I will come early

We do not usually say:

• If the lesson will start...

Hebrew works similarly here. After אם, Hebrew often uses the present tense to talk about a future condition:

• אם השיעור מתחיל... = If the lesson starts...
• not usually אם השיעור יתחיל... in this kind of sentence

So מתחיל is present in form, but in this context it refers to a future situation.

מתחיל is the masculine singular present-tense form of the verb להתחיל = to begin / to start.

Because השיעור is grammatically masculine singular, the verb matches it:

• השיעור מתחיל = the lesson starts
• If the subject were feminine, you would use מתחילה

For example:

• הפגישה מתחילה = the meeting starts

The prefix ב often means in, at, or on, depending on context.

With clock times, it usually means at:

• בחמש = at five
• בחמש וחצי = at five thirty

So the ב is the normal preposition used before the time.

Literally, חמש וחצי means five and a half.

That is the normal Hebrew way to say 5:30.

Examples:

• שלוש וחצי = 3:30
• שבע וחצי = 7:30

So:

• בחמש וחצי = at five thirty

Hebrew usually does not need a separate word for then in this kind of sentence, just like English often doesn’t.

English:

• If the lesson starts at 5:30, I’ll come early

Hebrew:

• אם השיעור מתחיל בחמש וחצי, אני אבוא מוקדם

The result clause naturally follows the condition, so then is understood.

Yes, אבוא by itself is often enough.

Hebrew verbs usually already show the subject, especially in the future tense:

• אבוא = I will come

So the sentence could also be:

• אם השיעור מתחיל בחמש וחצי, אבוא מוקדם

Adding אני can make the subject clearer or slightly more emphatic:

• אני אבוא מוקדם = I will come early

Both are natural.

The verb לבוא = to come is somewhat irregular.

Its future forms are:

• אבוא = I will come
• תבוא = you will come / she will come
• יבוא = he will come
• נבוא = we will come

So אבוא is simply the correct future form for I will come.

A useful pronunciation guide:

• אבוא is pronounced roughly a-VO
• The ו is part of the spelling of this verb form

Here מוקדם means early, and it functions like an adverb:

• אני אבוא מוקדם = I will come early

Hebrew often uses adjective forms in places where English uses adverbs.

So although מוקדם can also mean early as an adjective, in this sentence it describes how you will come.

Compare:

• הגעתי מוקדם = I arrived early
• הוא בא מוקדם = He came early

Yes.

You can also say:

• אני אבוא מוקדם אם השיעור מתחיל בחמש וחצי

That means the same thing: I’ll come early if the lesson starts at 5:30.

The original version puts the condition first, but both word orders are normal.

וחצי is pronounced roughly va-CHET-si.

A few pronunciation notes:

• The ו here means and, pronounced ve or va depending on sound environment
• ח is the throaty Hebrew sound that does not exist in standard English
• חצי means half

So חמש וחצי sounds roughly like:

• cha-MESH va-CHET-si