Learn Hardcore Polish: Mój kolega ma nowy komputer.

Mój is the masculine singular nominative form of the possessive pronoun “my.” It agrees in gender, number, and case with the noun it modifies. Other forms are:
• moja (feminine singular)
• moje (neuter singular)
• moi (masculine personal plural)
• moje (non-masculine plural)

Why is it mój and not moja or moje?

Because kolega is a masculine singular noun in the nominative case, the pronoun must match:
• Masculine sg. nom. → mój
• Feminine sg. nom. → moja
• Neuter sg. nom. → moje

What does kolega mean?

Kolega means “colleague,” “buddy,” or “male friend.” The feminine equivalent is koleżanka.

What is the role (case) of kolega in this sentence?

It’s the subject of the sentence, so it’s in the nominative case, singular, masculine.

What does ma mean?

Ma is the 3rd person singular present tense of the verb mieć (“to have”), meaning “he has.”
Present-tense conjugation of mieć:
• ja mam (I have)
• ty masz (you have)
• on/ona/ono ma (he/she/it has)
• my mamy (we have)
• wy macie (you pl. have)
• oni/one mają (they have)

Why aren’t there any articles like a or the in Polish?

Polish has no definite or indefinite articles. Both “a computer” and “the computer” are expressed simply as komputer, with context clarifying whether it’s specific or general.

Why is the adjective nowy ending in -y, and what case is nowy komputer?

Nowy (“new”) must agree with komputer (masculine singular). Here komputer is the direct object, so it’s in the accusative case. For inanimate masculine nouns, accusative form is identical to nominative, hence nowy komputer.
Adjective endings (masculine singular):
• Nominative: nowy
• Accusative (inanimate): nowy
• Accusative (animate): nowego

How do you pronounce this sentence?

Phonetic transcription:
mój ko-LE-ga ma NO-vih kom-PU-ter
IPA: [muj kɔˈlɛɡa ma ˈnɔvɨ kɔmˈputɛr]
(Stress in Polish usually falls on the penultimate syllable.)