W tym słowie akcent pada na pierwszą sylabę.

A very literal breakdown is:

• w = in
• tym = this
• słowie = word
• akcent = stress / accent
• pada = falls
• na = on / onto
• pierwszą = first
• sylabę = syllable

So the sentence literally means:

In this word, the stress falls on the first syllable.

That is also the most natural English translation.

Because the preposition w meaning in usually requires the locative case when it describes location.

So:

• dictionary form: słowo = word
• locative singular: słowie = in the word

And this has to match that noun in case, gender, and number:

• to słowo = this word
• w tym słowie = in this word

Also, słowo is neuter, which is why the base form is to słowo, not ten słowo.

Yes, akcent can mean accent, but in grammar and pronunciation it is also the normal word for stress.

So in this sentence:

• akcent = word stress

Polish often uses akcent where English would specifically say stress.
If you are talking about which syllable is emphasized, akcent is exactly the right word.

Yes, it is a very common expression.

• akcent pada na X = the stress falls on X

Polish commonly uses padać na in this context, just like English says falls on:

• Akcent pada na drugą sylabę. = The stress falls on the second syllable.
• Akcent pada na końcówkę. = The stress falls on the ending.

So this is a standard and natural way to talk about pronunciation.

Because the expression padać na takes na + accusative here.

The base forms are:

• pierwsza = first (feminine)
• sylaba = syllable

But after na in this expression, they become accusative singular:

• pierwszą
• sylabę

Also, the adjective must agree with the noun:

• sylaba is feminine
• so the adjective must also be feminine

That is why you get:

• na pierwszą sylabę = on the first syllable

Because it describes sylabę, and sylaba is a feminine noun.

In Polish, adjectives must agree with the noun they describe in:

• gender
• number
• case

So:

• pierwsza sylaba = the first syllable
• na pierwszą sylabę = onto/on the first syllable (accusative form)

The ending -ą in pierwszą is a typical feminine singular accusative/instrumental ending for adjectives.

A rough pronunciation guide is:

v tym SWO-vye AK-tsent PA-da na pyerf-SHOW sy-LA-beng

A few details:

• w is pronounced like English v
• tym has a Polish y, which is not the same as English ee
• słowie sounds roughly like SWO-vye
• akcent is AK-tsent
• pierwszą has rz pronounced like zh/sh depending on context; here roughly pyerf-SHOW
• sylabę ends with ę, which is nasal; at the end of a word it is often pronounced less strongly nasal in everyday speech

If you want the most important pronunciation point in the sentence, it is the phrase:

• pierwszą sylabę = the first syllable

The given word order is natural and standard:

• W tym słowie akcent pada na pierwszą sylabę.

But Polish word order is fairly flexible. You could also hear:

• Akcent w tym słowie pada na pierwszą sylabę.
• Na pierwszą sylabę pada akcent w tym słowie.
  This is more marked and less neutral.

The original version sounds clear and natural, especially in teaching or explanation.

Usually, no.

In standard Polish, stress most often falls on the penultimate syllable—that is, the second-to-last syllable.

So a sentence like this is often used when:

• a word is an exception
• the speaker wants to make pronunciation especially clear
• the word may be foreign or unusual
• the learner might otherwise stress the wrong syllable

So akcent pada na pierwszą sylabę often signals that this word does not follow the most typical Polish stress pattern.

Not normally in this context.

For pronunciation, Polish uses:

• akcent
• sometimes akcent wyrazowy = word stress

Nacisk usually means physical or figurative pressure, not linguistic stress.

So for syllable stress, the natural wording is:

• Akcent pada na pierwszą sylabę.

Here are the key dictionary forms:

• w = preposition
• ten / to = this
  In the sentence it appears as tym
• słowo = word
  In the sentence it appears as słowie
• akcent = stress / accent
• padać = to fall
  In the sentence it appears as pada
• na = preposition
• pierwszy = first
  In the sentence it appears as pierwszą
• sylaba = syllable
  In the sentence it appears as sylabę

This is useful because Polish often changes word endings depending on case and grammar, so the form you see in a sentence is often not the dictionary form.