How many phonemes in the word letters?

* l (as in "let") - 1 phoneme

* e (as in "bed") - 1 phoneme

* t (as in "top") - 1 phoneme

* er (as in "her") - 1 phoneme

* s (as in "sun") - 1 phoneme

Therefore, the word "letters" has 5 phonemes.