Sisulizer setup (Sisu.exe) installs Polar spell checker engine (PolarSpellChecker.dll) into Sisulizer directory (e.g. C:\Program files (x86)\Sisulizer 4). In addition of the engine file Polar needs a dictionary file as well. Dictionary file extension is .lex. Each language has its own dictionary file. For example SpellUS.lex contains English (US) dictionary. By default Sisulizer setup installs all 14 dictionary files. They are:
||English (United Kingdom)|
|SpellUS.lex||English (United States)|
If either engine file or a dictionary file that you need is not installed on Sisulizer directory you need to run Sisulizer setup again. Uninstall your current Sisulizer, remove the directory and run setup again. Make sure that you do not uncheck any languages that you might need.