Zákazník objevil novou službu.

Because zákazník is in the nominative singular, which is the case normally used for the subject.

• zákazník = customer
• It is a masculine animate noun.
• In this sentence, it is the person doing the action of discovering.

So Zákazník objevil novou službu means The customer discovered a new service, with zákazník as the doer of the action.

Because it is the direct object of the verb, so it has to be in the accusative case.

The base form is:

• služba = service (nominative)

But after a transitive verb like objevit (to discover), the thing being discovered goes into the accusative:

• služba → službu

So:

• novou službu = a new service / the new service depending on context

Because the adjective has to agree with the noun in gender, number, and case.

Here, služba is:

• feminine
• singular
• accusative

So the adjective nový (new) must also take the feminine singular accusative form:

• nová služba = nominative
• novou službu = accusative

That is why both words change:

• nová → novou
• služba → službu

Objevil is the past tense.

More specifically:

• infinitive: objevit = to discover
• past form: objevil = discovered

This particular form tells you the subject is:

• singular
• masculine

So zákazník objevil means the male customer discovered.

In Czech past tense, verbs typically use a form ending in -l (or a related ending), combined with forms of to be when needed.

Here:

• objevil is the masculine singular past participle-like form

Examples:

• objevil = he discovered
• objevila = she discovered
• objevilo = it discovered
• objevili = they discovered (masculine animate or mixed group)
• objevily = they discovered (non-masculine-animate)

In a sentence with a noun subject like zákazník, Czech usually does not need a separate pronoun like he.

Objevit is perfective.

That means it presents the action as completed: the customer successfully discovered the service.

So Zákazník objevil novou službu suggests a finished event.

Its imperfective partner is objevovat, which would be used for repeated, ongoing, or incomplete action.

Compare:

• objevil = discovered / found
• objevoval = was discovering, used to discover, or a more process-oriented meaning depending on context

Because Czech has no articles.

English says:

• a new service
• the new service

Czech just says:

• novou službu

Whether it means a or the depends on context.

So Zákazník objevil novou službu could mean either:

• The customer discovered a new service
• The customer discovered the new service

depending on the situation.

No, Czech word order is fairly flexible because case endings show grammatical roles.

The neutral, straightforward order here is:

• Zákazník objevil novou službu.
• subject + verb + object

But other orders are possible for emphasis:

• Novou službu objevil zákazník.
  Emphasizes the new service
• Objevil zákazník novou službu?
  Can sound like a question depending on intonation and punctuation

Even when the order changes, the endings still show who did what:

• zákazník is still the subject
• službu is still the object

You usually learn that from the dictionary form and from patterns in Czech grammar.

Zákazník means customer, referring to a person, so it is animate. It is also grammatically masculine.

This matters because masculine animate nouns behave differently from:

• masculine inanimate nouns
• feminine nouns
• neuter nouns

It affects:

• adjective agreement
• past tense forms
• some case endings

For example, if the subject were a female customer, the sentence would be:

• Zákaznice objevila novou službu.

Notice the verb changes from objevil to objevila.

The infinitive is objevit.

A simple breakdown is:

• objevit = to discover
• past masculine singular: objevil

Czech dictionaries list verbs in the infinitive, so if you want to look this up, search for objevit, not objevil.

Its imperfective partner is:

• objevovat

So you may see both:

• objevit = perfective
• objevovat = imperfective

It would become:

• Zákaznice objevila novou službu.

Two important changes happen:

1. zákazník → zákaznice
   because the noun now refers to a female customer

2. objevil → objevila
   because the past tense verb agrees with a feminine singular subject

The object stays the same:

• novou službu

A rough pronunciation guide is:

• Zákazník ≈ zaa-kahz-neek
• objevil ≈ ob-ye-vil
• novou ≈ no-voh
• službu ≈ sloozh-boo

A few useful pronunciation notes:

• á is a long vowel
• ž sounds like the s in measure
• ou is a diphthong, somewhat like oh said smoothly
• j is pronounced like English y

So the whole sentence sounds roughly like:

• zaa-kahz-neek ob-ye-vil no-voh sloozh-boo

Yes, it could.

Because Czech has no articles, zákazník can mean:

• the customer
• a customer

and novou službu can mean:

• a new service
• the new service

Without more context, English translation has to choose one possibility. Czech leaves that open unless the broader situation makes it clear.