It all works as it is designed. It means - mod will add Lang BBCode only when you have set user default language and only this language. If it is not appropriate, you can just tell to not add it in editor.
On all other cases you have to add lang BBCode manually. So you wrote messages in two other languages and you tell the mod that those are in French, but those are not and that is why those were not translated.
Translation of message written in other language will happen only when lang BBCode is added. Otherwise Google get confused and returns just same text (it is like you go to French-English translator and give him text in Polish - he will just give you this text back, because he will not understand it). So adding lang BBCode to message tells the mod to which translator he should go for translation.
Also please note that options to editors are added only if user has set his default language other that forum default language. Otherwise it has no sense because it means that user writes in forum language and there is no lang BBCode to add. So please for test just change your default language to other that forum language and you will see that options will appear in your editors
