Peřej má silný vodní proud.

Peřej means a rapid — a place in a river where the water moves very fast and becomes turbulent.

A few related words:

• řeka = river
• proud = current
• peřeje = rapids

So the sentence is talking about a rapid as a river feature.

Peřej is feminine.

For English speakers, this can feel strange at first, because many feminine Czech nouns end in -a, but not all of them do. Quite a few feminine nouns end in a consonant, especially words of patterns like:

• píseň = song
• dlaň = palm
• myš = mouse
• kost = bone

Peřej belongs to that general type of feminine noun ending in a consonant.

So in this sentence:

• peřej = feminine singular subject
• therefore the verb is má = has for he/she/it

Má is the 3rd person singular present tense of mít = to have.

Conjugation of mít in the present tense:

• já mám = I have
• ty máš = you have
• on / ona / ono má = he / she / it has
• my máme = we have
• vy máte = you have
• oni / ony / ona mají = they have

Since peřej is a singular noun, Czech uses má:

• Peřej má... = The rapid has...

It is in the accusative, because it is the direct object of má.

The structure is:

• Peřej = subject
• má = verb
• silný vodní proud = direct object

So literally:

• The rapid
  • has
    • a strong water current

A useful detail: proud is a masculine inanimate noun, and in the singular its accusative form is the same as its nominative form.

So:

• nominative: silný vodní proud
• accusative: silný vodní proud

That is why it does not visibly change here.

Because both adjectives agree with the noun proud.

In Czech, adjectives must match the noun in:

• gender
• number
• case

Here, proud is:

• masculine
• singular
• accusative (but same form as nominative because it is masculine inanimate)

So both adjectives take the matching form:

• silný = strong
• vodní = water / aquatic / relating to water
• proud = current

That gives:

• silný vodní proud

Because vodní is an adjective meaning water-related or of water, and proud means current.

So:

• voda = water
• vodní = water, aquatic, water-related
• proud = current, flow

Vodní proud literally means water current.

Could Czech sometimes use just proud? Yes, because in context it may already be obvious that we are talking about water. But vodní proud is perfectly natural and makes the meaning extra clear.

Because Czech does not have articles like English a/an/the.

So:

• Peřej can mean a rapid or the rapid
• silný vodní proud can mean a strong water current or the strong water current

Context tells you which interpretation is meant.

This is very normal in Czech, and learners have to get used to understanding definiteness from the situation instead of from articles.

This is the neutral, standard word order:

• subject + verb + object

So Peřej má silný vodní proud is the most straightforward version.

Czech word order is more flexible than English, so other orders are possible, but they usually change the emphasis.

For example:

• Silný vodní proud má peřej.
  This is possible, but it sounds more marked and emphasizes silný vodní proud.

For a learner, the safest default is:

• subject + verb + object

Roughly, peřej is pronounced something like PEH-rzhey.

A few points:

• stress is on the first syllable
• j is pronounced like English y
• ej sounds roughly like the ay in day
• ř is the famous Czech sound that does not exist in English

The Czech ř is often described as something between:

• r
• and zh as in measure

You do not need to master ř immediately. At first, many learners say something close to rž or zh, and native speakers will usually still understand you.

The plural is peřeje.

So:

• singular: peřej má = a rapid has
• plural: peřeje mají = rapids have

The main change you need to notice is:

• má → mají

So if the subject becomes plural, the verb must also become plural.

Here are the most useful singular forms:

• nominative: peřej
• genitive: peřeje
• dative: peřeji
• accusative: peřej
• locative: peřeji
• instrumental: peřejí

For this sentence, the important form is the nominative:

• Peřej má silný vodní proud.

A useful thing to notice is that peřej has the same form in:

• nominative singular
• accusative singular

That is normal for some feminine nouns of this type.