Version:            (using KDE 4.3.4)
Installed from:    Ubuntu Packages

(I'm reporting this against KMail, although it affects other KDE programs (and Chromium for example), too. Please re-assign as you see it fits best)

I'm changing between two languages often: German and English.
This is a common thing for non-native English speakers.

Therefore I think it would be sweet if I would not have to change the language of the spell checker (e.g. in KHTML text areas or the KMail messaging window) back and forth.
Instead, if there are e.g. more than 80% of errors in the first words (maybe 5?), it should internally compare it with the other languages that are setup and if it fits those, automatically change the language setting of the spell checker.

Use case:
I just wrote an email to a german friend, but now I'm writing this bug report.
When I start typing in the browser's text area, (almost) all words get underlined, which is quite distracting.
The spell checker engine/interface should recognize that it's assuming probably the wrong language and check if the text might be intended to be English instead.

For this to work best there should probably be a new setting "Auto" for the language to use (allowing the engine to automatically select the most appropriate/likely language).

(This _might_ even get applied on a per paragraph basis later, but something different - most of the time a text is written in a consistent language after all)