Zaliczka jest wysoka.

Zaliczka usually means an advance payment, down payment, or deposit paid in advance.

A useful distinction:

• zaliczka = money paid before the full payment, usually as part of the final price
• kaucja = a refundable security deposit (for example, for renting a flat)

So depending on context, zaliczka is often better translated as advance payment than as deposit.

Jest means is. It is the 3rd person singular form of być (to be).

So:

• zaliczka = the advance payment / deposit
• jest = is
• wysoka = high

Together: Zaliczka jest wysoka = The advance payment is high.

Because wysoka has to agree with zaliczka.

In Polish, adjectives change form to match the noun in:

• gender
• number
• case

Zaliczka is a feminine singular noun, so the adjective must also be feminine singular:

• masculine: wysoki
• feminine: wysoka
• neuter: wysokie

That is why we say zaliczka jest wysoka.

A very common clue in Polish is the ending -a.

Most nouns ending in -a are feminine, and zaliczka is one of them.

Because it is feminine, other words linked to it must also use feminine forms, such as:

• ta zaliczka = this deposit / this advance payment
• wysoka zaliczka = a high deposit

It is in the nominative case because it is the subject of the sentence.

So:

• zaliczka = nominative singular
• wysoka = nominative singular feminine, matching zaliczka

This is the basic dictionary form of both words in this sentence.

Because Polish does not have articles like English a and the.

So zaliczka can mean:

• a deposit
• the deposit
• an advance payment
• the advance payment

Which one is meant depends on context.

In standard Polish, no—you normally need jest here.

So:

• correct: Zaliczka jest wysoka.
• not standard: Zaliczka wysoka.

Polish does sometimes omit forms of to be in certain informal or special styles, but for a normal sentence like this, jest should stay.

Yes. Wysoki / wysoka / wysokie is very natural for things like:

• prices
• costs
• fees
• amounts
• payments

So wysoka zaliczka sounds natural.

Even though wysoki can also mean tall in other contexts, here it clearly means high.

Sometimes, but wysoka is more natural here.

Compare:

• wysoka zaliczka = a high advance payment / deposit
• duża zaliczka = a big deposit

Both are understandable, but for money, rates, costs, and amounts, Polish often prefers wysoki/wysoka where English uses high.

Yes, but Zaliczka jest wysoka is the most neutral word order.

Other orders are possible for emphasis, for example:

• Wysoka jest zaliczka. = It is the deposit that is high / The deposit is high indeed.

That sounds more marked or literary. For everyday use, stick with:

• Zaliczka jest wysoka.

A rough pronunciation guide:

• zaliczka ≈ za-LEECH-ka
• jest ≈ yest
• wysoka ≈ vih-SO-ka

Very roughly together:

• za-LEECH-ka yest vih-SO-ka

A few sound notes:

• z before a vowel is usually like English z
• cz sounds like ch in chop
• j sounds like English y
• y in Polish is not the same as English ee; it is a shorter, more central vowel

You could, but it changes the emphasis.

• Zaliczka jest wysoka. = neutral: The deposit is high.
• To zaliczka jest wysoka. = It is the deposit that is high / The deposit is the thing that is high

The version with to is more emphatic and depends on context. The plain sentence without to is the normal choice.

Not always. This is a very common learner issue.

In English, deposit can mean:

1. money paid in advance as part of a total price
2. a refundable security deposit
3. money put into a bank account

Polish usually uses different words:

• zaliczka = advance payment / part-payment
• kaucja = security deposit
• wpłata / depozyt = deposit into an account or formal deposit, depending on context

So be careful: zaliczka is not a universal translation of deposit.