This is a topic I’d never thought much about, but as Lilly PuTian says at Blogcritics.org, “If a keyboard is made, like many things, for the average man, then for the person who is smaller, much smaller than the average male, the keyboard is oversized.”
Lilly is under five feet tall, weighs less than 100 pounds, and has hands and feet that are small for her size. Regular full-sized keyboards are too large for her, with the keys spaced too far apart, leading to Repetitive Strain Injury and painful hands.
Her solution is to use a keyboard made for a child. She discusses the merits of two such keyboards. The Baby Keyboard from A4Tech is 2/3 the size of a normal keyboard. The distance between each individual keycaps was specially designed not only for kids’ small hands as well as for computer users with smaller hands. Datadesk Technologies’ LittleFingers keyboard is designed especially for kids’ hands.
Read Lilly’s story: Tech Review: Keyboards for Smaller Hands.
Other sources for small keyboards include: