There are two built-in spell checker engines available in oXygen: Hunspell/MySpell and a Java spell checker. The two formats of spell dictionaries are different so you need different dictionary files for each spell checker.
The spell checker used in OpenOffice, Mozilla and Chrome is also available in oXygen which comes with the following built-in dictionaries: English (generic, United States, United Kingdom, Canada), French, German (generic, Germany), Spanish (generic, Spain).
To add a new spelling dictionary to oXygen or to replace an existing one you should follow these steps.
If you cannot find a dictionary for your language you can build a dictionary that is compatible with Hunspell. Suppose you have a list of correct words which you want to check in your documents when you run the Hunspell checker. You can build a dictionary following these instructions.
You can download one of the most used dictionaries from the following list. Make sure you read the README file that comes with each dictionary. If you don't accept the license terms for a dictionary please do not use it.
oXygen provides built-in dictionaries only for the languages English (United States, Great Britain, Canada), French (France, Belgium, Canada, Switzerland) and German in the form of .dar files located in the directory [Oxygen-install-dir]/dicts.
Other dictionaries can be added by copying the corresponding dictionary to the directory [Oxygen-install-dir]/dicts and restarting oXygen. A Java spell checker dictionary is a binary file with the .dar extension and is obtained by compiling a list of the correct words of a language using the Dictionary Builder tool. The user documentation is available together with the tool. If you compile a .dar file with this tool and you want to test it in oXygen just copy the .dar file in the folder [Oxygen-install-dir]/dicts, restart oXygen and make sure the Java spell checker is selected in Options -> Preferences -> Editor -> Spell Check -- Spell Checking engine.
The following dictionaries are available free of charge and can be installed in oXygen for working with the Java spell checker: