The word "lethargus" is spelled with five letters which represent six sounds in IPA phonetic transcription. The first sound /l/ is represented by the letter "l". The second sound /ɛ/ is represented by the letter "e". The third sound /θ/ is represented by the letter "th". The fourth sound /ɑ/ is represented by the letter "r". The fifth sound /g/ is represented by the letter "g". The final sound /əs/ is represented by the letters "us". Therefore, the spelling of "lethargus" accurately represents its pronunciation.
Sleeping-sickness.
A practical medical dictionary. By Stedman, Thomas Lathrop. Published 1920.