Costilow is a surname that is spelled using the phonetic transcription /kɔːstiːloʊ/. This means that the first syllable of the word is pronounced with an open-o sound (similar to the word "saw"), and the second syllable is pronounced with a long "ee" sound. The third syllable is pronounced with a low "oh" sound, followed by a long "o" sound. The combination of sounds in each syllable creates the unique spelling of this surname, which is not commonly found in English.