אם תבואי לכנס מחר, אחותי תסיע אותנו לשם לפני העבודה.

Because Hebrew marks gender in the second person singular.

• תבואי = you will come when speaking to one female
• תבוא = you will come when speaking to one male

So this sentence is addressed to a woman or girl. If you were talking to a man, it would be:

אם תבוא לכנס מחר, אחותי תסיע אותנו לשם לפני העבודה.

That is a very common difference between English and Hebrew.

In Hebrew, with a real future condition, it is normal to use the future tense in both parts:

• אם תבואי... = if you come
• אחותי תסיע... = my sister will drive

So Hebrew says literally something closer to if you will come, my sister will drive us, even though natural English does not say it that way.

This is standard Hebrew usage, not a special nuance.

Usually, no. Hebrew often leaves out subject pronouns because the verb already shows who the subject is.

Here, תבואי already tells you:

• second person
• singular
• feminine

So את is unnecessary unless you want emphasis or contrast.

For example:

• אם תבואי... = neutral
• אם את תבואי... = if you come... with extra emphasis

Because Hebrew future forms can sometimes be ambiguous by themselves.

תסיע can mean:

• she will drive
• you (masculine singular) will drive

But in this sentence, the subject אחותי comes right before the verb:

• אחותי תסיע... = my sister will drive...

Since אחותי is feminine singular, the meaning must be she will drive.

תסיע comes from להסיע, which means to drive someone, to give someone a ride, or to transport someone by car.

So:

• אחותי תסיע אותנו = my sister will drive us / give us a ride

This is different from לנהוג:

• אחותי תנהג = my sister will drive (the car)
• אחותי תסיע אותנו = my sister will drive us somewhere

So להסיע focuses on the passengers being taken somewhere.

Because אותנו is the direct object form: us.

The verb להסיע takes a direct object:

• להסיע מישהו = to drive someone / give someone a ride

So:

• אחותי תסיע אותנו = my sister will drive us

לנו means to us or for us, which does not fit this verb here.

Compare:

• היא רואה אותנו = she sees us
• היא נותנת לנו = she gives to us

לשם means there, often with a sense of to there or toward there.

In this sentence, motion is involved, so לשם is very natural:

• אחותי תסיע אותנו לשם = my sister will drive us there

You may also hear שם in casual speech, especially conversationally:

• אחותי תסיע אותנו שם

But לשם sounds a bit more precise here because the idea is movement to a destination.

In unpointed Hebrew writing, לכנס can be ambiguous.

It can represent:

• לכנס = to a conference
• לכנס = to the conference

The difference is in pronunciation/vowels, not in the plain spelling:

• le-kenes = to a conference
• la-kenes = to the conference

So without vowel marks, context usually tells you which one is meant.

Hebrew often uses העבודה where English would simply say work.

So:

• לפני העבודה = before work

This can mean:

• before going to work
• before the workday starts
• before work begins

depending on context.

Also, לפני already means before, so you do not add another preposition before העבודה.

Not with the same meaning.

• אם = if
• כש or כשת... = when

So:

• אם תבואי לכנס מחר... = if you come to the conference tomorrow...
• כשתבואי לכנס מחר... = when you come to the conference tomorrow...

Using אם leaves the coming uncertain. Using כש suggests that the coming is expected or treated as a given future event.

Yes. Hebrew allows that.

You can say:

אחותי תסיע אותנו לשם לפני העבודה אם תבואי לכנס מחר.

That is grammatical.

The version with the אם clause first is often more natural when you want to present the condition before the result:

• אם תבואי..., אחותי תסיע...

In writing, a comma is commonly used when the conditional clause comes first.

Yes. Hebrew word order is fairly flexible, especially with time words like מחר.

Possible alternatives include:

• אם מחר תבואי לכנס...
• אם תבואי מחר לכנס...

The original order,

• אם תבואי לכנס מחר...

is completely natural and neutral. Moving מחר usually changes emphasis slightly, not the basic meaning.