Learn Polish: Moje serce zawsze bije mocniej. - My heart always beats harder.

The basic adverb for "hard" or "strongly" is mocno. To form the comparative for most regular adverbs ending in -o, you drop the -o and add -iej. So, the root mocn- plus -iej gives us mocniej (harder/stronger).

Can mocniej also mean "stronger"?

Yes! The root word mocny translates to "strong," "firm," or "hard." When talking about a heart beating, the wind blowing, or holding onto something, mocniej can naturally translate to either "harder" or "stronger" in English.

What is the infinitive (dictionary form) of the verb bije?

The infinitive is bić. It means "to beat" (like a heart or a drum) or "to hit." Because it is a short verb, it has a slightly irregular conjugation, adding a -j- in the present tense. For "it beats" (third-person singular), it becomes bije.

Why is the word for "my" spelled moje here instead of mój or moja?

Because serce (heart) is a neuter noun. You can often spot neuter nouns because they end in -e or -o (like okno or zdjęcie). The word for "my" has to match the gender of the noun it belongs to, so we use the neuter form moje instead of the masculine mój or the feminine moja.