There are various ways to combine letters to make different sounds; different court reporters use different theories in their work. Historically, reporters often created "briefs" (abbreviations) on-the-fly, and sometimes mixed theories, which could make it difficult for one reporter to read another reporter's notes; but current versions of theories are primarily designed for computerized translation using a standardized dictionary provided by the company that promulgates the theory, which forces reporters to stick with one theory and use only the specific combinations in that company's dictionary. However, it is not uncommon for students and reporters to add a significant number of entries to a stock dictionary (usually when creating briefs of their own).