The spelling of the name "Chrisstie" may appear unusual. However, the reason for this spelling lies in the pronunciation of the name. The addition of the second "s" represents a prolonged "s" sound, which is pronounced /s/ in IPA transcription. This elongated sound is derived from the Greek origin of the name, where the double "s" represents the Greek letter sigma (Σ), which denotes a long "s" sound. Therefore, the spelling of "Chrisstie" is a representation of the unique pronunciation of the name.