Read the accent; learn the spelling

Greek has stress, not lexical tone. Pitch still rises and falls with questions and feeling. Compare yes and Yes?: the melody changes, the word does not.

The tonos tells you which vowel is strong in a multisyllable lowercase word. The accent stays part of spelling: πότε means when, ποτέ means ever or never in context.

Ι, η, υ, ει and οι normally represent the same i sound. In τυρί, cheese, υ and ι both say i.

You can read them, but listening alone cannot choose between their spellings. We learn the spelling of each word visually, and never make those spellings rival answers to a sound cue.