Effects of Long-Term Ageing on Speaker Verification

The changes that occur in the human voice due to ageing have been well documented. The impact of these changes on speaker verification is less clear. In this work, we examine the effect of long-term vocal ageing on a speaker verification system. On a cohort of 13 adult speakers, using a conventional GMM-UBM system, we carry out longitudinal testing of each speaker across a time span of 30-40 years. We uncover a progressive degradation in verification score as the time span between the training and test material increases. The addition of temporal information to the features causes the rate of degradation to increase. No significant difference was found between MFCC and PLP features. Subsequent experiments show that the effect of short-term ageing (<5 years) is not significant compared with normal inter-session variability. Above this time span however, ageing has a detrimental effect on verification. Finally, we show that the age of the speaker at the time of training influences the rate at which the verification scores degrade. Our results suggest that the verification score drop-off accelerates for speakers over the age of 60. The results presented are the first of their kind to quantify the effect of long-term vocal ageing on speaker verification.