User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20100101 Firefox/7.0.1 Build ID: 20110930092603 Steps to reproduce: I tried to use both english and french dictionaries for spell checking. Actual results: It is not possible to choice two dictionaries. I can change the language when I writing a email but it takes a lot of time (using the mouse, select the language, ...). Expected results: Thunderbird should be able to use several (two or more) dictionaries together. Today lots of people use two or more language in their jobs/lifes. I know it is not a big problem for English speakers because of the predominant use of this language but it is very important for the others.

Do you want several dictionaries used simultaneously in the same message? Or do you wish TB to automatically switch dictionary depending on some language marker in the message or block of text?

I had in mind the first solution (several dictionaries used simultaneously in the same message) but even the second solution is also a good one but maybe less quick if you have to set the language marker.

I had bug 338427 in mind, where firefox will be able to switch to the correct dictionary according to the language of the page. Maybe something like that could be leveraged in Thunderbird, if there is any language marker in the message. So you wish to write in several languages in the same message? Something like in MS Word, where you also have to mark text and set the language of it? Then you can have blocks of text with different language and when you click into a block, the correct dictionary is selected.