Some experiments have been carried out to study and compensate for within-speaker variations in speaker verification. To induce speaker variation, a speaking behaviour elicitation software package has been developed. A 50-speaker database with voluntary and involuntary speech variation has been recorded using this software. The database has been used for acoustic analysis as well as for automatic speaker verification (ASV) tests. The voluntary speech variations are used to form an enrolment set for the ASV system. This set is called structured training and is compared to neutral training where only normal speech is used. Both sets contain the same number of utterances. It is found that the ASV system improves its performance when testing on a mixed speaking style test without decreasing the performance of the tests with normal speech.