Hi there alanjh this is easily done
- Open up WLM and hit the ALT key, then go Tools>Options at the top.
- Go to the Spelling Tab.
- Scroll Down until you find French, click it then click "Install" WLM will download the French Dictionary (this can take a few minutes)
- Then click "Set Default"
- Click OK
- Write your message.
- When your done, follow the above steps, but change the default back to your default language,
After you've done this, you'll have the French Dictionary to use whenever you want it. It looks like it has to be set as Default for WLM to recognise it though, I couldn't find an option to "check spelling with French dictionary" I had to set it as the default dictionary