Against the backdrop of cognitive load theory (CLT) it was tested if irregular voice increases processing demands on working memory (WM). An experiment was designed to expose N = 54 participants to expos- itory text delivered with a modal and a creaky human voice. Working memory capacity was measured by a secondary task on the visual modality. Listening to a creaky voice quality consumes more cognitive capacity as indicated by the significant decrease in secondary task performance; also, retention of infor- mation was found to be impaired. Results are explained within the framework of CLT and implications for professional communication are discussed.