Choosing talkers for the BKB/A Speechreading Test: A procedure with observations on talker age and gender

A procedure is described for choosing talkers for the BKB/A (BKB/Australian version) Speechreading Test. The main aims were: to select several talkers from a pool of potential talkers, to avoid adventitiously choosing a markedly atypical single talker; to assess speechreading as a general skill rather than as talker-specific; and to select talkers who were acceptable to speechreaders, relatively easy to speechread, and comparable in their speechreadability. Because of the number of variables involved and the demanding nature of the task for speechreaders, a three-stage selection procedure was adopted. In the resulting BKB/A 21-sentence list Speechreading Test, four of the 16 sentences in a list are each spoken by four talkers, chosen as follows. In Stage 1, 16 talkers (four of each age/gender set: older men, older women, younger men, younger women) were selected from an original pool of 40 (10 of each set), via rankings made by eight hearing-impaired judges with speechreading experience. In Stage 2, the final four talkers (one of each set) were selected from the 16 via the speechreading scores of further hearing-impaired subjects with speechreading experience. In Stage 3, the order of talker appearance within lists (in random order versus over blocks of four consecutive sentences) was determined. This three-stage approach to talker selection identified differences between talker candidates within sets, except for younger men, and suggested that, overall, younger women were the easiest to speechread. The discussion addresses the merits and disadvantages of this approach to talker selection, and suggests some reasons for the documented differences in speechreadability among talkers of different age and gender.The results presented so far showed that the judges generally agreed in ranking talker speechreadability, and generally could differentiate amongst talkers, within tapes, but also suggested differences between talker genders and an interaction between talker age and gender. These outcomes support the contention that appropriate choice of talkers for a speechreading test is an important issue. Thus, it seems wise to use a variety of talkers in a speechreading test of general applicability.Selection of the subgroup of 16 talkersRankings for each talker were collated and the means and standard deviations of the ranks were calculated. The two talkers with mean ranks closest to rank 1 (the most speechreadable) were selected from each tape of five talkers, provided that the selection identified the same talkers in both AV and VO conditions, and that no negative comment (e.g. a physical feature seen as a distraction) was made about a talker by more than one judge. In this way, 13 of the required 16 talkers were chosen. For the remaining three talkers, further selection criteria were applied, in the order: talker ranks with comparable SDs, and talker age (the oldest talker was chosen for OM or OW and the youngest talker for YM or YW, to maximize differences between ages), provided no negative comments were made by more than one judge.Thus, at the end of Stage 1, the procedure described led to the selection of 16 possible talker candidates for the final videotape, two from each of the two tapes of five talkers, for each of the age/gender sets: OM, OW, YM, and YW. These candidates were judged as relatively easy to speechread and were acceptable to the speechreader judges.Stage 2: Selection of the final four talkers from the subgroup of 16There is little or no published research showing that the gender or age of talkers are factors in speechreading, whereas the findings of Stage 1 suggested that both genders and different ages be chosen, giving some representation of the broad talker population. Such representation would not, however, be general as only the most speechreadable talkers were selected, for the reasons given above.The aim of Stage 2 was to choose four talkers from the subgroup of 16 identified at the conclusion of Stage 1. The choice was to be made primarily on the basis of mean speechreadability scores (rather than judgements of speechreadability) comparable across age/gender sets, and comparable SDs. Stage 2 was designed as four separate studies, one for each of the four talker sets:OM, OW, YM, YW.