Girl is pronounced GURL (IPA /ɡɜːrl/). One syllable — curl tongue for 'r' and end with 'l' smoothly.
IPA: /ɡɜːrl/
Syllables: GURL
Common ESL mistake: Learners say 'gar-ul' splitting it into two syllables.
Tip: One syllable — curl tongue for 'r' and end with 'l' smoothly.