The format for the "loadable dictionaries" is the same as the format for the Jar files. The only difference is that these "loadable dictionaries" are stored in the file system of the device (normally the dictionaries are stored in the Jar-file). This would solve the problem of limitations of the Jar file size that several low-cost devices have; but currently the "loadable dictionaries" are not really usable on most devices, cause of the missing certificate and the plenty of confirmation messages (
http://dictionarymid.sourceforge.net/jsr75.html).
For DfM support for any format may be implemented in the translation layer; or as this was done in the past, support for additional formats may be implemented as a preprocessor which generates a cvs file that is then run through DictionaryGeneration (the DICT-format is supported as such a preprocessor).
Regards,
Gert