First of all it looks really good (familiar actually ;)). And it works with form builder, so yes, great.
When we implemented the select boxes some time ago, we faced exactly your suggestion (wanting to edit the whole text) but decided the back button is your friend.
Furthermore, what happens if you mistype a word, that aspell does not recognize and therefore are not able to change it. We thought of javascript popups or some other things, but again back button is your friend.
Concerning the language, we decided to go with a select box that offers "no spellcheck" by default and all the languages that aspell has installed for the rest. But your idea is great. We should order the drop down box by local preference ;). But I'm not sure if Ola's solution of checking aspell without ns_aspell supports multiple languages for each widget at the same time.
