Sprawdzamy wysokość brzegu rzeki.

Sprawdzamy means we check / we are checking.

The ending -my shows 1st person plural, so the subject is we.

It comes from the verb sprawdzać = to check.
A few present-tense forms are:

• sprawdzam = I check
• sprawdzasz = you check
• sprawdza = he/she/it checks
• sprawdzamy = we check
• sprawdzacie = you all check
• sprawdzają = they check

In Polish, the subject pronoun my (we) is usually omitted, because the verb ending already tells you who is doing the action.

It can mean either one, depending on context.

Polish present tense often covers both:

• we check
• we are checking

So Sprawdzamy wysokość brzegu rzeki could mean:

• We check the height of the river bank
• We are checking the height of the river bank

If you need to know which one is meant, the wider context usually tells you.

Because wysokość is a noun, meaning height.

Compare:

• wysoki / wysoka / wysokie = high (adjective)
• wysokość = height (noun)

In this sentence, we need a noun because we are checking the height, not describing something as high.

Also, the correct spelling is wysokość, not wysokośći.
It is a feminine noun ending in -ość, and in the dictionary form it is:

• wysokość = height

Because brzegu is in the genitive case.

The noun wysokość often takes a following noun in the genitive, just like English the height of ...

So:

• brzeg = bank / shore
• wysokość brzegu = the height of the bank

This is a very common Polish pattern:

• kolor domu = the color of the house
• koniec filmu = the end of the film
• wysokość brzegu = the height of the bank

So brzeg changes to brzegu because it depends on wysokość.

For the same reason: it is also in the genitive case.

Here the structure is:

• brzeg rzeki = the bank of the river

So:

• rzeka = river
• rzeki = of the river

The full phrase is built step by step:

• wysokość = height
• brzegu = of the bank
• rzeki = of the river

So literally it is:

• height of bank of river

Natural English: the height of the river bank

The sentence breaks down like this:

• Sprawdzamy = we are checking
• wysokość = the height
• brzegu rzeki = of the river bank

And inside that last part:

• brzegu = of the bank
• rzeki = of the river

So the main object is wysokość.
Then brzegu rzeki tells you whose height it is.

A useful way to see it is:

Sprawdzamy [wysokość [brzegu rzeki]].

Because Polish has no articles like a or the.

So Polish often leaves that idea to context.

• rzeka can mean a river or the river
• brzeg rzeki can mean a river bank or the river bank
• wysokość brzegu rzeki can mean the height of the river bank or a river bank’s height, depending on context

In normal translation, English usually needs the, so we add it naturally: We are checking the height of the river bank.

You could say My sprawdzamy, but usually you wouldn’t unless you want emphasis.

Polish normally drops subject pronouns when the verb ending already shows the subject.

So:

• Sprawdzamy = We are checking
• My sprawdzamy = We are checking / It is we who are checking

Using my adds emphasis or contrast, for example:

• My sprawdzamy wysokość brzegu rzeki, a oni mierzą głębokość.
  We are checking the height of the river bank, and they are measuring the depth.

Yes, Polish word order is more flexible than English, because case endings show grammatical relationships.

The neutral order here is:

• Sprawdzamy wysokość brzegu rzeki.

But you may also see variations such as:

• Wysokość brzegu rzeki sprawdzamy.
• Brzegu rzeki wysokość sprawdzamy.

These alternatives are usually more marked and may sound literary, emphatic, or context-driven.

For a learner, the safest natural version is:

Sprawdzamy wysokość brzegu rzeki.

Yes, both can be possible, but they are not exactly the same.

• sprawdzać = to check
• mierzyć = to measure

So:

• Sprawdzamy wysokość brzegu rzeki = We are checking the height of the river bank
• Mierzymy wysokość brzegu rzeki = We are measuring the height of the river bank

If the idea is verifying or inspecting a height, sprawdzać fits.
If the idea is actually taking the measurement, mierzyć is often more precise.

A rough English-friendly guide is:

• wysokość ≈ vih-SO-koshch
• brzegu ≈ BZHE-goo
• rzeki ≈ ZHE-kee

A few helpful notes:

• w sounds like English v
• rz usually sounds like zh as in measure
• sz sounds like sh
• ś/si sounds like a softer sh
• ć/ci sounds like a soft ch
• ó sounds like u

The hardest cluster for many learners is brz- in brzegu.

It depends on context.

• brzeg can mean bank, shore, or edge
• with rzeka (river), bank is often the most natural choice
• with morze (sea) or jezioro (lake), shore may be more natural

So:

• brzeg rzeki = river bank
• brzeg jeziora = lake shore
• brzeg morza = seashore / shore of the sea

In this sentence, the river bank is the best translation.

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

However, there is an extra detail: for many feminine nouns like wysokość, the nominative and accusative forms look the same.

So:

• wysokość = nominative singular
• wysokość = accusative singular

That is why the form does not change visibly here.

Structure:

• Sprawdzamy → verb
• wysokość → direct object, so accusative
• brzegu rzeki → genitive phrase depending on wysokość