I realise different addons may be used. But there is a facility to use a personal dictionary [[Using the spell checker]] Is it easy to create and switch dictionaries other than by employing addons. For instance can I create my own personal dictionaries of various types eg - medical - slang - personal If I did create such dictionaries would they be likely to work with some of the addons or not. I ask because a single inflexible spell checker may not always meet my needs. I can always paste text from firefox into another more suitable spellchecker or application, but it would be more convenient to be able to modify the dictionaries firefox uses, according to what I wish to be checked on a specific item/session