Mail Crashes and Keyboard Inoperative after Running Language-Removal App


On advice from a popular website I downloaded and ran an App called Monolingual to free up around 2GB of hard-disk space by removing unwanted languages from the OS (obviously leaving the English languages unchecked)

I now discover the following problems:

(i) Mail appears to be functioning normally until I open an individual email and try and reply or forward, whereupon the program instantly crashes, with the resulting info box giving me a long list of errors.

(ii) The keyboard is completely inoperable, which means I can't even use Time Machine (assuming I would know what to do) because I can't type in my Mac password.

(iii) Thinking that it may have been a coincidental keyboard failure, I unplugged it and re-tried Mail - but with the same results.

Everything else appears normal (other programs don't crash) with the only problem in evidence being this failure to be able to type.

Any ideas?
Yes, "advice from a popular website" doesn't equate to _good_ advice.
I speak from sad experience, having done the same as you with Monolingual.
And, even though Monolingual is fairly simple, and does its job well, it's also _easy_ to set monolingual to do too much.
I suspect that you went to one of the other tabs, and chose to remove some of the keyboard layouts.
And, because you removed resources from all over, even Time Machine may not really get you back, unless you simply restore your complete backup.
However, you will probably need to reinstall OS X.
Boot to your Recovery system, if you have Lion or newer.
Boot to your installer DVD if you have Snow Leopard or older.
Either way, do a simple reinstall of OS X. You'll get your system working again, and you won't lose anything (except time)

Don't get me wrong about Monolingual. I still use it occasionally. Just don't choose to remove resources other than languages that you don't need.
Finally, you might need to reinstall some third-party apps. I do know that MS Office 2008 stops working if you remove the language resources (even if you keep your own language).
Thank you, DeltaMac, that was really useful (and humbling.)

With your help the Mac engineer that came over to fix this was able to do it more quickly (and therefore more cheaply.) He did exactly as you said, as far as I could tell. (In case you're wondering, I guess I was just too chicken to do it myself.)