I'm working on the same spellchecker Aspell, but there is a problem with accents, due to the format.
K-Meleon uses UTF8, Aspell directories use ANSI, and but it's not blocking, Aspell display uses OEM, and if it works, the display is trash.
I know there is no accents in english, and that's why, as the extension was given for en-US, there is no problem.
I have contacted a french guy refered on the french aspell page, but he only maintains the french dictionnary. I'm about to contact the mailist, for the last problem I was talking about.
I have ask also to Dorian for an execwait function in macro. It would be nice, not to need external tools in AutoIt or VisualDialogScript.
Mozilla/5.0 (x11; U; Linux x86_64; fr-FR; rv:38.0) Gecko/20100101 Ubuntu/12.04 K-Meleon/76.0
Mail : alain [dot] aupeix [at] wanadoo [dot] fr
Ubuntu 12.04 - Gramps 3.4.9 - Harbour 3.2.0 - Hwgui 2.20-3 - K-Meleon 76.0 rc