בין אם מקדמה ובין אם תשלום לפי התקדמות, נשלם מחר.

It is a fixed Hebrew pattern meaning whether ... or ....

So:

• בין אם מקדמה ובין אם תשלום לפי התקדמות = whether it is an advance payment or a progress-based payment

This structure introduces two alternatives, and then the main clause tells you what happens in either case.

Because that is the normal Hebrew pattern.

Standard Hebrew usually says:

• בין אם X ובין אם Y

Literally, it is something like:

• whether if X and whether if Y

But in natural English, you would usually just translate it as whether X or Y.

The repetition is not a mistake; it is how the construction is built in Hebrew.

Good question. Yes, the sentence is somewhat elliptical, which is very common in Hebrew.

The first part gives two noun-phrase alternatives:

• מקדמה = advance payment
• תשלום לפי התקדמות = payment according to progress

Hebrew often leaves out words that are easy to understand from context. A more fully expanded version could be:

• בין אם זו מקדמה ובין אם זה תשלום לפי התקדמות, נשלם מחר
• בין אם נשלם מקדמה ובין אם נשלם לפי התקדמות, נשלם מחר

But the shorter version sounds natural, especially in practical or business-like language.

Because they are being used indefinitely here.

• מקדמה = an advance payment
• תשלום = a payment

If the speaker meant specific, already-known options, you might see:

• המקדמה
• התשלום לפי ההתקדמות

Without ה־, the sentence sounds more general: one option is an advance payment, the other is a payment based on progress.

מקדמה usually means an advance payment: money paid before the full job, service, or delivery is completed.

Depending on context, English translations can include:

• advance payment
• deposit
• down payment

But advance payment is often the safest general meaning.

לפי means according to, based on, or in accordance with.

התקדמות means progress.

So:

• תשלום לפי התקדמות = payment based on progress
• in business English, this might also be phrased as progress payment or payment according to milestones/progress

It means the payment depends on how much of the work has been completed.

Without ה־, it sounds more general or category-like: payment according to progress.

With ההתקדמות, it would sound more specific:

• לפי ההתקדמות = according to the progress / according to the progress made

Both are possible, but the version without ה־ is very natural when naming a payment method or type.

Here נשלם is understood as the 1st person plural future of לשלם (to pay):

• נשלם = we will pay

Hebrew often includes the subject inside the verb itself, so there is no need for a separate אנחנו.

The word מחר strongly supports this reading:

• נשלם מחר = we will pay tomorrow

So the ending and the context together make the meaning clear.

Yes. Both are possible.

• נשלם מחר = neutral, straightforward word order
• מחר נשלם = puts a little more focus on tomorrow

Hebrew word order is flexible. In this sentence, the writer first gives the alternatives, then gives the main result:

• בין אם ... ובין אם ..., נשלם מחר

That structure is very natural.