US-based Method for Speech Reception Threshold Measurement in French

We propose a new method for measuring the threshold of 50% sentence intelligibility in noisy or multi-source speech communication situations (Speech Reception Threshold, SRT). Our SRT-test complements those available e.g. for English, German, Dutch, Swedish and Finnish by a French test method. The approach we take is based on semantically unpredictable sentences (SUS), which can principally be created for various languages. This way, the proposed method enables better cross-language comparisons of intelligibility tests. As a starting point for the French language, a set of 288 sentences (24 lists of 12 sentences each) was created. Each of the 24 lists is optimized for homogeneity in terms of phoneme-distribution as compared to average French, and for word occurrence frequency of the employed monosyllabic keywords as derived from French language databases. Based on the optimized text material, a speech target sentence database has been recorded with a trained speaker. A test calibration was carried out to yield uniform measurement results over the set of target sentences. First intelligibility measurements show good reliability of the method.