The speech of two patients with tardive dyskinesia was studied, and one neuroleptic-treated patient having no signs of overt tardive dyskinesia served as control. A structured interview, including reading, repetition of sentences, and spontaneous conversation, was performed. A phonetic transcription and analysis of abnormal phonemes was done by a linguist under blind conditions. Both patients with tardive dyskinesia had abnormal phonemes whereas the control patient had none. These differences could not be explained by age, direct neuroleptic effect, or neuroleptic exposure time. The abnormal phonemes were all consonants. The authors conclude that tardive dyskinesia may cause articulatory communication problems.