Learn Croatian: Oprostite, ne čujem dobro. - Excuse me, I do not hear well.

To make a verb negative in Croatian, you simply put the word ne directly before the verb. Unlike English, you don't need helper words like 'do' or 'does'. So, čujem is 'I hear', and ne čujem is 'I do not hear'. The particle ne and the verb are always written as two separate words, except for a few special verbs you will learn later.

Why isn't the word for 'I' (ja) used in this sentence?

Croatian often drops subject pronouns like ja (I) because the verb ending already tells you who is doing the action. The -m ending in čujem specifically means 'I hear', so saying ja ne čujem is usually unnecessary unless you want to heavily emphasize that you are the one who cannot hear.

Is oprostite a formal or informal way to say 'excuse me'?

Oprostite is the formal and plural form. You use this when speaking to a stranger, an older person, or a group of people. If you were speaking to a single friend, a family member, or a child, you would use the informal version, oprosti.

Doesn't dobro usually mean 'good'? Why is it translated as 'well' here?

In Croatian, the word for 'good' (adjective) and 'well' (adverb) are the exact same word: dobro. Because it is paired with the verb čujem in this sentence, it describes how you hear, so it translates to 'well'.