How to add dictionnary to Gourmet

Which language are you looking for? From the translations you contributed on Launchpad, I guess it's Canadian French (fr_CA).
We currently don't have that, but we do have French (as spoken in France, fr_FR). So you could try to run

LC_ALL="fr_FR.utf-8" gourmet

from a terminal and see if it gives you the UI in French.

Thank you for the answer. What I am looking for is to add French (from France) dictionary to gourmet. I do not really want to change the UI in French. Just add different language dictionary.

Okay, sorry for the misunderstanding.
Unfortunately, I'm still not sure what you mean by dictionary: the inline spellchecking of recipe instructions and notes? You can select them, right-click the selection and change the language settings for the selected portion.

Or do you mean the cuisine/category/ingredient key suggestions?

What I meant, I should have been more specific, is the inline spell checking of recipe instructions , notes, ...

When I right click, I only do have en, en_CA, en_GB, en_US. What I would like to do is to add the French dictionary to the list. My machine is in English, but I could if necessary add the french locale.

Thank you again for this wonderful product.

To solve this, I think you really need to add a (system-wide) French locale.
(From Ubuntu's upper right "gear" symbol menu, select "System Settings", then "Languages", which is where you can add new locales.)

Installing French system wide did the trick. Now I do have en and fr dictionary available for inline spell checking. Thank you for your help.

PS: I will continue the translation when time is available.