The spelling of "Derril" can be confusing due to its irregular pronunciation. In IPA phonetic transcription, it is spelled as /ˈdɛrɪl/. The "e" is pronounced as "eh" and the double "r" as a rolled "r" sound. The "i" is pronounced as "ih" and the final "l" as a soft "l" sound. It is essential to pay attention to the phonetics to spell this word correctly. While it may seem like an easy word to spell, the irregular pronunciation can lead to mistakes.