V korytě je voda.

Because v meaning in takes the locative case when it describes a location.

• Dictionary form: koryto
• Locative singular: korytě
• So: v korytě = in the trough / in the channel

This is a very common pattern in Czech. The noun changes form after certain prepositions:

• v domě = in the house
• v městě = in the city
• v korytě = in the trough

So koryto is the base form, but after v you need korytě here.

It is locative singular.

In this sentence:

• v = in
• korytě = locative singular of koryto

The locative is used after certain prepositions, especially when talking about a place where something is.

So the structure is:

• V korytě = in the trough
• je voda = there is water / the water is

Koryto can mean a few related things depending on context:

• a trough for animals
• a channel
• a riverbed

In a simple learner sentence like V korytě je voda, the most likely idea is a trough or a channel-like container/place that can hold water.

So the exact English word depends on context, but the grammar stays the same.

Je is the 3rd person singular of být = to be.

So:

• je = is

In Czech, sentences like this often use je where English might say either:

• There is water in the trough
• The water is in the trough

Czech uses být normally in this kind of sentence. In standard Czech, you should keep je here.

Because voda is the subject of the sentence, so it is in the nominative case.

Here:

• voda = nominative singular
• je = is
• v korytě = in the trough

Even though English often starts with there is, Czech does not need a separate word for there in this sentence. The noun itself stays nominative:

• Je voda. = There is water.
• V korytě je voda. = There is water in the trough.

Because Czech has no articles.

So voda can mean:

• water
• the water
• sometimes even some water

And korytě can mean:

• in a trough
• in the trough

The exact meaning depends on context, not on separate words like a or the.

That is one of the biggest differences from English.

Yes. Czech word order is flexible, and changing it changes the focus or emphasis, not usually the basic meaning.

For example:

• V korytě je voda.
  Focuses first on the location: In the trough, there is water.
• Voda je v korytě.
  Focuses more on water as the topic: The water is in the trough.

Both are grammatical. The version you were given sounds natural if the important new information is that the trough contains water.

Approximately: KO-ri-tyeh

A few important points:

• Czech stress is usually on the first syllable: KO-rytě
• The ě is not pronounced like a separate ye after a hard t; it softens the t, so tě sounds like a soft ťe
• So korytě is better thought of as ko-ry-ťe than as plain ko-ryt-ye

Also in the whole sentence:

• V before k is pronounced like f
• je sounds like yeh

So V korytě je voda is approximately:

f KO-ri-tyeh yeh VO-da

Very often, yes, but not always perfectly.

In this sentence, v clearly means in because something is located inside a place:

• v korytě = in the trough

A useful contrast is:

• v korytě = in the trough
• na korytě = on the trough

So here v is exactly the right preposition because the water is inside the trough/channel, not on top of it.

It can suggest either one depending on context, because Czech has no articles and uses flexible word order.

But this particular word order, V korytě je voda, often feels a bit more like:

• There is water in the trough

It presents the location first and then tells you what is there.

If you said:

• Voda je v korytě

that more naturally sounds like:

• The water is in the trough

So the difference is not absolute, but word order gives a clue about what is being emphasized.