How many phonemes in the word thoroughly?

* th - /θ/ (one phoneme)

* o - /oʊ/ (one phoneme)

* r - /r/ (one phoneme)

* ou - /ʌ/ (one phoneme)

* gh - /ɡ/ (one phoneme)

* l - /l/ (one phoneme)

* y - /i/ (one phoneme)

Therefore, the word "thoroughly" has 7 phonemes.