Podziwiam jego odwagę, bo nie boi się mówić po polsku.

Because odwagę is the direct object of podziwiam (I admire), and podziwiać takes the accusative case.

• dictionary form: odwaga = courage
• accusative singular: odwagę

This is a very common pattern with feminine nouns ending in -a:

• kawa → kawę
• książka → książkę
• odwaga → odwagę

So Podziwiam jego odwagę literally has the structure I admire his courage.

Because jego means his, while swój / swoją refers back to the subject of the same clause.

Here, the subject of podziwiam is an implied I. So:

• Podziwiam jego odwagę = I admire his courage
• Podziwiam swoją odwagę = I admire my own courage

So swój would point back to I, not to he.

Because jego works differently from words like mój, twój, or nasz.

Compare:

• moja odwaga
• mojego brata
• moją książkę

Here mój changes form.

But jego usually stays the same when it means his:

• jego brat
• jego siostra
• jego odwaga
• jego książkę

So even though odwagę is feminine accusative, jego remains jego.

Polish often omits subject pronouns because the verb form usually tells you who the subject is.

• podziwiam = I admire
• boi się = he/she is afraid

So ja is not necessary before podziwiam.

In the second clause, boi się could mean he is afraid or she is afraid, but the context tells us it is he.

Adding the pronouns is possible, but usually only for emphasis:

• Ja podziwiam jego odwagę...
• ...bo on nie boi się mówić po polsku.

Because in Polish, a comma is normally used before conjunctions like bo when they introduce an explanatory clause.

So:

• Podziwiam jego odwagę, bo nie boi się mówić po polsku.

This is standard punctuation.

In English, punctuation around because can be different, so this often feels unfamiliar to learners.

Both can mean because, but they differ in style.

• bo = very common, natural, everyday
• ponieważ = more formal, more written

So this sentence could also be:

• Podziwiam jego odwagę, ponieważ nie boi się mówić po polsku.

That is correct, but it sounds a bit more formal. In normal speech, bo is usually the more natural choice.

The verb is bać się, which means to be afraid or to fear. The się is part of the verb and cannot normally be left out.

So the basic verb is not just bać in this meaning, but bać się.

Some forms are:

• boję się = I am afraid
• boisz się = you are afraid
• boi się = he/she is afraid
• boimy się = we are afraid

So nie boi się means he is not afraid.

Because after bać się you often use the infinitive to say what someone is afraid to do.

• boi się mówić = is afraid to speak
• boi się zapytać = is afraid to ask
• boi się wejść = is afraid to enter

If you said mówi, that would be a finite verb form (he speaks / is speaking) and it would not fit this structure.

So:

• nie boi się mówić po polsku = he is not afraid to speak Polish

Because mówić and powiedzieć are different in aspect and meaning.

• mówić = to speak / to be speaking in a general or ongoing sense
• powiedzieć = to say / to tell / to say once

Here the meaning is general: he is not afraid to speak in Polish, not just to say one thing. That is why mówić is the natural choice.

Compare:

• nie boi się mówić po polsku = he is not afraid to speak Polish
• nie boi się powiedzieć tego po polsku = he is not afraid to say that in Polish

Po polsku means in Polish.

This is the normal Polish way to talk about speaking a language:

• mówić po polsku = to speak Polish
• mówić po angielsku = to speak English
• mówić po niemiecku = to speak German

For a learner, it is best to treat po + language form as a set pattern.

So:

• po polsku = in Polish
• po angielsku = in English
• po hiszpańsku = in Spanish

Because in Polish, names of languages and most nationality adjectives are written with lowercase letters.

So Polish writes:

• polski
• angielski
• niemiecki

not with capitals.

This is different from English.

Compare:

• English: Polish
• Polish: polski

But proper nouns like country names do use capitals:

• Polska = Poland
• Anglia = England

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

The original sentence is the most neutral and natural:

• Podziwiam jego odwagę, bo nie boi się mówić po polsku.

But other orders are possible for emphasis, for example:

• Jego odwagę podziwiam, bo nie boi się mówić po polsku.
• Bo nie boi się mówić po polsku, podziwiam jego odwagę.

These versions are grammatical, but they sound more marked or emphatic. For most learners, the original order is the safest and most natural one.