Ratio is pronounced RAY-shoh (IPA /ˈreɪʃoʊ/). Two syllables — 'RAY-shoh' with 'sh' instead of 't'.
IPA: /ˈreɪʃoʊ/
Syllables: RAY · shoh
Common ESL mistake: Learners say 'rah-tee-oh' with three syllables and a /t/ sound.
Tip: Two syllables — 'RAY-shoh' with 'sh' instead of 't'.