Acoustic and electropalatographic data on the so-called Hiberno-English ‘slit-t’ are reported, and the implications these data have for an adequate transcription are discussed. Previous transcription suggestions highlight the difficulty posed by the lack of an IPA diacritic for tongue shape. We conclude that the adoption of an alveolar diacritic (as used in the extensions to the IPA for transcribing disordered speech) could get round these difficulties.