Spanish · Pronunciation Guide
oon, one syllable — the u is the "oo" of "boot", not the "uh" of English "un-".
One unstressed syllable, leaning on the noun after it. Its longer form "uno" stands alone when no noun follows, and stresses U-no; "un" is what you get when the word drops its ending before a masculine noun, and it never takes a beat of its own.
Listen: un
Free browser voice. Hear it read by a real native speaker inside the LingoDrop app.
Quiero un café.
I want a coffee.
Listen: Quiero un café.
Free browser voice. Hear it read by a real native speaker inside the LingoDrop app.
"Quiero un café" ends on a word with a written accent: "café" ends in a vowel, so the default rule would give CA-fe, and the accent pulls the stress to the final é. Meanwhile "un café" runs together as oon-ka-FEH. "Quiero" opens with qu, so the u there is silent — a nice contrast with the u in "un", which is the entire vowel.
English has a prefix spelled the same way — "unhappy", "undo" — and readers borrow its vowel, producing "uhn". Spanish u is always "oo". Then there is the article's other half: masculine nouns take "un", feminine ones take "una", and getting that wrong is more noticeable to a listener than any vowel error. Note the exception in "un agua", where a feminine noun starting with a stressed a takes the masculine article purely for sound.