Configure Dictionaries
To get spell-check for your preferred language in commit messages, you can use OpenOffice/LibreOffice dictionary files.
Example
Download the French dictionary from this link.
Rename the downloaded .oxt file to .zip and unpack that file.
In the directories directory you can find some .dic (and .aff) files.
In SmartGit’s preferences, page Spell Checker, click Add and select the appropriate .dic file.
Now you can select in the context menu of the commit message input field which spell checker to use.