''Once people use 'Mavis,' they think they see her name in other places around the country,'' Ms. Hankin said. ''They envision that maybe they saw her on a show.'' Even once the truth is revealed, some people are not convinced. ''There was one man who kept calling back,'' Ms. Hankin recalled. ''He could not believe it. He kept asking questions, and saying 'Are you sure?' ''

Mavis was brought to life almost 12 years ago, in initially rudimentary form, by Les Crane, Walt Bilofsky and Joe Abrams for their software company, Software Toolworks, then located in Sherman Oaks, Calif. The first version of ''Mavis,'' which used just four colors on screen and came on 5 1/4-inch floppy disks, was shipped in the fall of 1987. In the early years, Mavis was little more than a photo on the box. She made her way into the program only gradually.

But on the programming end, the first version offered what were then some fairly advanced features, like pop-up windows and flexible navigation, so the user didn't always have to return to the main menu to select another area of the program. The product's release came only about half a year after planners had approved the concept, in the spring of 1987. The complex code was written quickly, not by a huge development team, but by just a few programmers working nonstop through the summer.

''Three guys, three computers, three beds, in four months,'' is how Mr. Bilofsky, the main programmer, recalled it. ''That was a really intense experience.''

A lot has changed between then and the release of the latest ''Mavis Beacon.'' Version 9 was coded by dozens of people, with a full year to work between upgrades. The program has also grown. It is now a fully interactive CD-ROM that features snazzy full-color graphics, music to type by (selections from classical to Motown), Internet support, a typing-game arcade and a digitized Mavis presiding over the classroom. The CD-ROM is available for both Macintosh and Windows.

Apart from the allure of Mavis, another feature that helps make the program such an understanding and sympathetic tutor is its proprietary Adaptive Response Technology. The software can analyze a user's keystrokes and adjust the drills and lessons to the appropriate level.

After a dozen years on the market, Mavis has gone through a few modest makeovers, usually with each new version of the software. ''She tends to change as much as people change their looks, really,'' Ms. Hankin said. ''We change her clothes according to the new styles. We change her hairstyle. We change her overall appearance.