In phonetics, preaspiration's a period of voicelessness or aspiration preceding the closure of a voiceless obstruent, basically equivalent to an [h]-like sound preceding the obstruent. In other words, when an obstruent's preaspirated, the glottis's opened for some time before the obstruent closure. To mark preaspiration using the International Phonetic Alphabet, generally the diacritic for regular aspiration (a superscript "h", [ʰ]),'s placed before the preaspirated consonant. Preaspiration… (More on Preaspiration)