Learn Hardcore Polish: Ona lubi mówić po polsku.

The verb form lubi is the same for he / she / it, so Polish often keeps the pronoun here to avoid ambiguity, especially in short, isolated sentences.

In a longer context, if it is already clear that we are talking about a woman, you could drop the pronoun and just say Lubi mówić po polsku.

Why is it lubi and not something like lubię or lubią?

Because lubi is the present tense form of lubić (to like) for he / she / it.

Present tense of lubić:

ja lubię – I like
ty lubisz – you like (singular, informal)
on / ona / ono lubi – he / she / it likes
my lubimy – we like
wy lubicie – you like (plural)
oni / one lubią – they like

Since the subject is ona (she), the correct form is lubi.

Why is mówić in this form and not mówi? And where is the “to” from “to speak”?

Mówić is the infinitive form, equivalent to English to speak.

In Polish, after verbs like lubić (to like), chcieć (to want), musieć (must, have to), etc., you use the infinitive:

Ona lubi mówić po polsku – She likes to speak Polish.
Ona chce mówić po polsku – She wants to speak Polish.

You do not add a separate word for to. The infinitive mówić itself corresponds to to speak.

Mówi is the present tense form (he/she/it speaks), and it works in a different sentence:

Ona mówi po polsku – She speaks Polish. (a statement of ability / fact)
Ona lubi mówić po polsku – She likes to speak Polish. (she enjoys doing it)

What does po polsku literally mean, and why not po polski?

Po polsku is a fixed expression meaning in Polish / in the Polish language.
You use po + language adjective in a special -sku form to say “in [a language]” when talking about speaking:

po polsku – in Polish
po angielsku – in English
po niemiecku – in German
po francusku – in French

Po polski is incorrect in this context.
Polski is the basic adjective form (“Polish” as a describing word), but po polsku is the adverb-like form used after mówić to express the language of speech.

Is po polsku always used with languages, or can I say mówi po angielski too?

You should always use the -sku form after po for languages in this pattern:

Correct:

mówi po polsku – speaks Polish
mówi po angielsku – speaks English
mówi po hiszpańsku – speaks Spanish

Incorrect:

✗ mówi po angielski
✗ mówi po polski

There is another, more formal way:

mówi w języku polskim – literally “speaks in the Polish language”

But in everyday speech, mówić po polsku / po angielsku / po niemiecku is the normal pattern.

Why is polsku not capitalized, when Polish is capitalized in English?

In Polish, adjectives derived from country or language names are written with a lowercase letter:

polski – Polish
angielski – English
niemiecki – German

So we write:

po polsku
po angielsku

The country name itself is capitalized:

Polska – Poland
Anglia – England
Niemcy – Germany

So the rule is different from English: languages and national adjectives are not capitalized in Polish unless they begin the sentence.

Can I change the word order, like Lubi ona mówić po polsku or Ona po polsku lubi mówić?

Polish word order is flexible, but different orders can sound more or less natural and can change the emphasis.

Ona lubi mówić po polsku. – neutral; the most natural basic sentence.
Lubi mówić po polsku. – also neutral if the context already makes it clear who we mean.

Other orders:

Lubi ona mówić po polsku. – possible, but sounds unusual or emphatic; you might hear something like this in poetry or special stylistic contexts.
Ona po polsku lubi mówić. – grammatically possible, but sounds a bit marked; it puts extra emphasis on po polsku (as if contrasting it with other languages).

For normal conversation, stick to Ona lubi mówić po polsku or, in context, Lubi mówić po polsku.

What is the difference between mówić and rozmawiać in a sentence like this?

Both can appear with po polsku, but they focus on slightly different things:

Ona lubi mówić po polsku.
She likes speaking Polish (using the language, talking in Polish in general).
Ona lubi rozmawiać po polsku.
She likes talking / having conversations in Polish (chatting with people in Polish).

Mówić is more general: to speak, to talk, to be able to use a language.
Rozmawiać emphasises a two‑way conversation.

Why do we use mówić, not powiedzieć, in this sentence?

In Polish, verbs come in aspects: imperfective (ongoing, repeated, general) and perfective (single, completed events).

mówić – imperfective: to speak, to be speaking, to speak in general
powiedzieć – perfective: to say/tell once (a single completed act)

Lubić (“to like”) normally combines with imperfective verbs, because liking something usually refers to a general or repeated activity:

Ona lubi mówić po polsku. – She likes speaking Polish (in general, habitually).

A sentence like ✗ Ona lubi powiedzieć po polsku is wrong, because powiedzieć describes a single completed act, which does not fit the idea of “liking to do something (in general).”

How would this sentence change for different subjects, like I, we, or they?

You keep mówić po polsku the same and just change the subject pronoun and the form of lubić:

Ja lubię mówić po polsku. – I like to speak Polish.
Ty lubisz mówić po polsku. – You (singular, informal) like to speak Polish.
On lubi mówić po polsku. – He likes to speak Polish.
Ona lubi mówić po polsku. – She likes to speak Polish.
My lubimy mówić po polsku. – We like to speak Polish.
Wy lubicie mówić po polsku. – You (plural) like to speak Polish.
Oni lubią mówić po polsku. – They like to speak Polish (group with at least one man).
One lubią mówić po polsku. – They like to speak Polish (all‑female group or non‑male things).

Notice that only lubić changes; mówić po polsku stays in the infinitive.

How would I say this in the past or the future: “She liked to speak Polish” / “She will like to speak Polish”?

Past tense:

Ona lubiła mówić po polsku. – She liked to speak Polish.

Future tense (grammatical, but not very common in everyday use):

Ona będzie lubić mówić po polsku. or
Ona będzie lubiła mówić po polsku.

Both mean roughly: She will like to speak Polish, but Polish speakers rarely talk this way about future liking. More natural would be to talk about starting to like it:

Ona zacznie lubić mówić po polsku. – She will start to like speaking Polish.

Why is lubić used here, and not kochać or uwielbiać?

These verbs express different strengths of feeling:

lubić – to like
uwielbiać – to love / to adore (very strong liking)
kochać – to love (people, sometimes things, very strong and emotional)

So you can say:

Ona lubi mówić po polsku. – She likes to speak Polish.
Ona uwielbia mówić po polsku. – She absolutely loves / adores speaking Polish.

Kochać is usually for people (or very strong, emotional attachment), so Ona kocha mówić po polsku sounds exaggerated and unusual.

How do you pronounce the tricky sounds in lubi, mówić, and polsku?

Approximate English-like guidance:

lubi – LU‑bee
- u like oo in food
- stress on LU
mówić – MOO‑veech
- ó is pronounced like u in food (same as u)
- wi like vee
- ć is a soft sound, something like ch in cheap but softer and more “palatal”
- stress on MÓ
po polsku – po POL‑skoo
- po like poh
- pol like pol in Poland
- ł in polsku is pronounced like English w in water: polsku → pol‑skoo but with a w‑like consonant: powskoo
- stress on POL

Remember: in Polish, the stress is almost always on the second‑to‑last syllable of each word: O‑na, LU‑bi, MÓ‑wić, POL‑sku.