The spelling of the word "grullon" is unique and can be explained using IPA phonetic transcription. The first letter, "g," is pronounced as a voiced velar stop, followed by an "r" sound produced by the back of the tongue raised towards the roof of the mouth. The double "l" is pronounced as a geminate consonant, held for a slightly longer duration. Finally, the "on" sound is produced by rounding the lips and creating a nasal sound through the nose. Overall, the spelling of "grullon" accurately represents its pronunciation.