הוא לא יכול לבוא איתנו היום, אבל מחר הוא יבוא איתך.

Because the two clauses express different ideas:

• הוא לא יכול לבוא = he cannot come / he is not able to come
  Here, יכול means can / is able to.
• מחר הוא יבוא = tomorrow he will come
  Here, יבוא is the future-tense verb will come.

So the first clause talks about ability/possibility today, while the second talks about what will happen tomorrow.

לבוא is the infinitive form of the verb to come.

In Hebrew, infinitives usually begin with ל־, which often corresponds to English to:

• לבוא = to come
• ללכת = to go
• לעשות = to do / to make

After a verb like יכול (can), Hebrew uses the infinitive:

• הוא יכול לבוא = he can come

So לבוא is exactly what you would expect after יכול.

In Hebrew, לא negates the verb or verbal idea that follows it.

So:

• הוא יכול לבוא = he can come
• הוא לא יכול לבוא = he cannot come

Putting לא before יכול is the normal way to say cannot / is not able to.

Hebrew often attaches pronoun endings directly to certain prepositions.

The word here is עם / את / אית־ in the sense of with, and with pronoun endings it becomes forms like:

• איתי = with me
• איתך = with you
• איתו = with him
• איתה = with her
• איתנו = with us
• איתם / איתן = with them

So:

• איתנו = with us
• איתך = with you

These are very common forms and worth memorizing as vocabulary items.

In unpointed Hebrew spelling, איתך can represent either:

• אִתְּךָ = with you (masculine singular)
• אִתָּךְ = with you (feminine singular)

So in normal writing, the same spelling may be used for both. Usually the context tells you which one is meant.

In this sentence, if no extra context is given, איתך could mean with you addressed to either a man or a woman.

Yes, Hebrew could leave it out here.

Because יבוא already shows he will come, the second הוא is not strictly necessary. You could also say:

• הוא לא יכול לבוא איתנו היום, אבל מחר יבוא איתך.

That still means the same thing.

Why include הוא anyway?

• for clarity
• for balance between the two clauses
• for a slightly more natural spoken rhythm in some contexts
• to emphasize he, as opposed to someone else

So the repeated הוא is completely normal, but not always required.

יבוא is the 3rd person masculine singular future form of the verb בוא (come).

So:

• לבוא = to come
• יבוא = he will come

This verb is a little unusual because its root behavior is not as straightforward as some regular verbs, so it is best learned as a common verb family:

• בא = he comes / came
• באה = she comes / came
• יבוא = he will come
• תבוא = she will come / you will come
• לבוא = to come

Yes, Hebrew word order is flexible here.

This sentence says:

• לבוא איתנו היום = to come with us today

But היום could also appear in another position, for example:

• הוא לא יכול היום לבוא איתנו
• היום הוא לא יכול לבוא איתנו

These versions can sound slightly different in emphasis, but they are all natural.

The original version is very normal and straightforward.

Putting מחר near the beginning gives it emphasis and sets the time frame right away:

• אבל מחר הוא יבוא איתך = but tomorrow he’ll come with you

Hebrew often puts time expressions early in the sentence, especially when contrasting times:

• היום ... מחר ...
• עכשיו ... אחר כך ...
• אתמול ... היום ...

Here the contrast is important:

• today he can’t come with us,
• but tomorrow he’ll come with you.

So starting the second clause with מחר is very natural.

Yes. אבל is the most common everyday word for but.

In this sentence, it simply connects two contrasting ideas:

• he can’t come with us today
• but tomorrow he’ll come with you

You may also see other contrast words in Hebrew, but אבל is the standard basic one to learn first.

Yes, but the meaning changes.

• הוא לא יכול לבוא איתנו היום = he can’t come with us today
  This focuses on inability / impossibility / being unable.
• הוא לא יבוא איתנו היום = he will not come with us today
  This focuses more on the fact that he won’t come.

So לא יכול לבוא is about can’t, while לא יבוא is about won’t / will not.

Hebrew does not use an auxiliary do the way English does.

In English, you often need do/does/did for negatives and questions:

• He does not come
• Does he come?

Hebrew usually does this without a helper verb like do:

• הוא לא בא = he does not come / he isn’t coming
• הוא בא? = is he coming? / does he come?

In this sentence, Hebrew simply says:

• הוא לא יכול = he cannot

No extra verb like does is needed.

Hebrew allows some flexibility, especially with time expressions and pronouns.

The original sentence is:

• הוא לא יכול לבוא איתנו היום, אבל מחר הוא יבוא איתך.

Possible variations include:

• הוא לא יכול לבוא היום איתנו, אבל מחר הוא יבוא איתך.
• היום הוא לא יכול לבוא איתנו, אבל מחר הוא יבוא איתך.
• הוא לא יכול לבוא איתנו היום, אבל הוא יבוא איתך מחר.

These all mean roughly the same thing, though the emphasis shifts a little.

So the sentence has a natural default word order, but it is not completely rigid.

A simple pronunciation guide is:

hu lo yaKHOL laVO iTA-nu haYOM, aVAL maKHAR hu yaVO iT-KHA

A few notes:

• הוא = hu
• לא = lo
• יכול = ya-khol
• לבוא = la-vo
• איתנו = i-ta-nu
• היום = ha-yom
• אבל = a-val
• מחר = ma-khar
• יבוא = ya-vo
• איתך = it-kha or i-takh, depending on gender

The kh sound is like the guttural sound in German Bach or Scottish loch.

Yes, this is completely natural modern Hebrew.

It sounds like normal everyday speech and writing. Nothing about it is unusually formal, literary, or old-fashioned.

A native speaker could absolutely say this in a normal conversation, for example when explaining changing plans.

A very useful pattern here is:

subject + לא יכול + infinitive
= subject + cannot + verb

For example:

• אני לא יכול לבוא = I can’t come
• היא לא יכולה ללכת = she can’t go
• אנחנו לא יכולים להישאר = we can’t stay

And another useful pattern is:

time word + subject + future verb

• מחר הוא יבוא = tomorrow he will come
• מחר אני אדבר = tomorrow I will speak
• מחר הם יגיעו = tomorrow they will arrive

So this sentence is a great model for two common Hebrew structures:

1. cannot + infinitive
2. future action with a time word like היום / מחר