For Windows Live Mail, I can not install for Spell-checking purposes “French” as a third language

I have installed on my new Windows 10 Desktop PC "Windows Live Mail". I do not remember the details of the Installation process; but the result is a working Live Mail, with a support of English and German Spell-Checking. 

Since (like many other in Switzerland) I am often writing emails, in German, in English or in French, I would like (same as on my old Windows 7 PC)  to be able to also have the option of a French Spell-Checking. In contrast to my new Office 365 copy  I was not able to customize Windows Live Mail to support also as a third language a French Language spellchecking (I do not wish to use Outlook, because I have no time to learn about it and to become efficient with its use),

I followed the following instructions found in the Internet  to install an additional language to Windows Live Mail:

1)       Launch Windows Live Mail

2)       Click on the "Datei" tab (=File Tab in English?)

3)       Click on Options

4)       Click on Mail…

5)       When th Options Window pops up, switch to the Spelling tab

I then see  in the lower part of the Window following languages which have been installed:

·       -   4 German language variations (2 versions for Germany, one for Austria, one for Switzerland)

·        -  and 4 english language variations

But I see no possibility to install another language (e.g. French) as an additional language, while the Internet descriptions suggest, that I would be able to install other languages. Could you please help me? 

Notice that I found a Post dated August 2, 2014 posted by JeanLizotte and answered by jFiredog an August 2, 2014. But it did not help.

Thank You very much in advance for your assistance.