"Oswalt" is a surname that is pronounced as "AHZ-wawlt" in IPA phonetic transcription. The "O" sound is represented by the "AH" phoneme, while the "S" in "Oswalt" is pronounced with a voiced "Z" sound, hence the "Z" phoneme. The "W" and "L" sounds in the word are also clearly pronounced. The silent "T" at the end is not represented in the IPA transcription, making the spelling somewhat confusing for those unfamiliar with the name.