Bonne année et bonne sante!

 Sandra,

           And the same to you and yours!! 

           Now I can say, "Aieeeeeeeeeeeeee!!  You've asked a question that's going to require a complicated answer!"  I am basing this on Windows Live Mail 2012, but it probably carries back at least a couple of versions.  If not, you may want to upgrade to Windows Live Mail 2012, henceforth known as WLM.

           You cannot specify sections of messages to be spell-checked versus not spell checked, but you can set up spell checking to use multiple dictionaries so that it will not flag words commonly used in messages that have two languages mixed as incorrect.

           What comes next is the step-by-step on what you need to open and tweak.  Without JAWS in front of me I can't say what it will announce, but most of the keyboard shortcuts are based in WLM.  If I type something such as ALT+F,O,M that means hit ALT+F, followed by O, followed by M.

1.  ALT+F,O,M   Opens the File Menu, Options, Mail.   You will now have a dialog box up that contains tabs, and I can't remember how to jump among tabs in a dialog, but you want to get yourself to the Spelling Tab.

2.  On the Spelling tab toward the bottom, there is a list box with the label, "Languages," just above it.  The languages are not listed alphabetically, don't ask me why.  On my installation of WLM, which is straight default settings, English in 4 versions are installed, United States, United Kingdom, Australia, and Canada.  Far beneath these you eventually hit "French (France)."  Select that.

3.  To the immediate right of the language list box are four buttons:  Install, Uninstall, Update, and Set Default.  You will want to select Install and activate the button to add French to the list of dictionaries that the spell-checker uses.  This is where I bow out, at least as far as knowing precisely what happens after you hit Install, since I don't want to install another language for my own spell-checker.  I imagine you'll get some sort of status box telling you about installation progress and completion.

4.  At the bottom of the whole Dialog box are three buttons, OK, Cancel, and Apply.  At this point just hit the OK button.

At this point French should be part of the spell-checker's recognized words, and you should stop being nagged nearly as often as you have been.

Hope this helps in some way.

Brian