1. A system for modifying a classification scheme for classifying hand-written characters, said system comprising: a memory storing the classification scheme so as to include a plurality of classes and user dependent weighted allographs, each class representing a respective letter and containing one or more of the allographs, each allograph including an associated weighting and representing a respective style of a respective letter and containing one or more prototypes, each prototype representing a variation in the respective allograph and being represented as a prototype vector, each prototype vector being formed from a number of values, each value quantifying a respective feature of the respective prototype vector; and a processor configured for: receiving data representing at least one handwritten character; determining a selection value based on the similarity of the received character and a respective prototype vector of the stored classification scheme; selecting a respective one of the prototype vectors of the stored classification scheme in accordance with the determined selection value; selecting a class of the stored classification scheme in accordance with the selected prototype representing the character to thereby determine the letter represented by the character; selecting one of the stored user dependent weighted allographs in accordance with the weightings and in accordance with said selected prototype vector representing the character; modifying one or more of the allographs in the respective class in accordance with the selection by modifying the weighting of said one or more of the allographs; and storing a modified classification scheme which includes said modified allographs.