LOS ANGELES (AP) _ Lots of people lose their voices. Somebody stole Glenn Gershan's.

Gershan, unable to speak because of cerebral palsy, uses an electronic keyboard to ''talk.'' The keyboard was stolen when somebody swiped his backpack as he ate lunch in the cafeteria at Valley College.

''I need the machine for my class, and for a messenger job I have applied for,'' Gershan, 31, told the Los Angeles Times this week, using a telephone communications device. ''I would say to anyone who knows me, please return it.''

Gershan was one of the first people to master the device. The keyboard, a 16-year-old prototype, was stolen Oct. 21.

''He is very good on this machine, but to someone else it would be a toy,'' said Jan Toppel, his mother. ''Anyone else would think it was a computer, open it up, see it has no value and probably trash it.''

Toppel said Gershan has overcome doctor's predictions that he would never walk and is able to run, jump and drive a car. Despite having the mental capacity of a 13-year-old, he has been able to live on his own for the last three years.

The voice machine, a 9 1/2 -by-11-inch keyboard that weighs about 4 pounds, lets Gershan program and store phrases and words, spell out words and make new ones using a combination of 26 phonetic keys, said Rick Pimentel, the vice president of Phonic Ear, which manufactured it.