Spoluúčast a záloha jsou vysoké.

Because the subject is plural: spoluúčast a záloha = two things joined by a (and).

• je = is for one thing
• jsou = are for more than one thing

So:

• Záloha je vysoká. = The deposit is high.
• Spoluúčast a záloha jsou vysoké. = The deductible/copay and the deposit are high.

They are in the nominative, because they are the subject of the sentence.

In this sentence, the structure is basically:

• spoluúčast a záloha = the subject
• jsou = the verb
• vysoké = the description/predicate adjective

So Czech is saying: Deductible and deposit are high.

Because vysoké agrees with a plural subject.

Each noun by itself is feminine singular:

• spoluúčast je vysoká
• záloha je vysoká

But when you put them together with a (and), the subject becomes plural, so the adjective also becomes plural:

• spoluúčast a záloha jsou vysoké

For this type of plural, Czech uses vysoké.

Yes.

• spoluúčast is feminine
• záloha is feminine

That is why, in the singular, you would say:

• Spoluúčast je vysoká.
• Záloha je vysoká.

When combined, they take a plural verb and plural adjective:

• Spoluúčast a záloha jsou vysoké.

Because Czech has no articles.

English says:

• the deductible
• a deposit

Czech simply uses the noun itself:

• spoluúčast
• záloha

Whether something is the, a, or just a general idea is understood from context.

So Spoluúčast a záloha jsou vysoké can naturally correspond to English with the.

It can change, although this sentence has a very neutral, standard word order.

Neutral version:

• Spoluúčast a záloha jsou vysoké.

You might also see:

• Záloha a spoluúčast jsou vysoké.
• Vysoké jsou spoluúčast a záloha.

The basic meaning stays the same, but changing the order can shift the focus or emphasis a little. For a learner, the given version is the safest and most natural default.

Because it is a normal Czech compound noun.

It is built from:

• spolu- = together, shared
• účast = participation

In real usage, spoluúčast often means a patient’s share of the cost, co-payment, or deductible, depending on context.

So even if English might use a multi-word expression, Czech often uses this single compound word.

A helpful rough pronunciation is:

spoh-loo-OO-chast a ZAA-lo-ha ysoh VISS-oh-kay

A few useful points:

• ou in jsou is like the vowel in go followed by a light oo glide
• á, ú, é are long vowels
• č sounds like ch in chair
• š sounds like sh
• Czech stress is usually on the first syllable of each word:
  • SPOluúčast
  • ZAloha
  • JSOU
  • VYsoké

Yes. That is possible.

• a = and
• i can mean something like and also / both ... and

So:

• Spoluúčast a záloha jsou vysoké. = neutral The deductible and the deposit are high.
• Spoluúčast i záloha jsou vysoké. = slightly more like Both the deductible and the deposit are high.

The version with a is the most straightforward basic form.

Because vysoké is not functioning like high in high fees. It is part of the predicate, like are high.

Compare:

• vysoká záloha = a high deposit
  Here the adjective directly modifies the noun.

• Záloha je vysoká. = The deposit is high.
  Here the adjective comes after the verb and describes the subject.

Your sentence is the second type:

• Spoluúčast a záloha jsou vysoké.

So the structure is very similar to English X and Y are high.

You would switch everything back to singular:

• Spoluúčast je vysoká.
• Záloha je vysoká.

Notice the changes:

• jsou → je
• vysoké → vysoká

That is because each noun on its own is feminine singular.

No. In this sentence it means high in the sense of large/expensive/costly, not physically tall.

So with money, fees, prices, deductibles, or deposits, vysoký / vysoká / vysoké often means:

• high
• large
• steep

For example:

• Cena je vysoká. = The price is high.
• Poplatky jsou vysoké. = The fees are high.

So in your sentence it refers to a high amount, not literal height.