i accidentally uninstalled some of the english language files but not all of them. now some items such as garage band or chess are in different languages. yes i used monolingual and i know it warns you. i thought you needed to check the boxes that you wanted to keep, but clearly not. So how can i reinstall this language package back to my mac?
Yeah.... I was about to mention that the most painless way to do it would be a clean install of OSX. Should only take about 1/2 hour and most likely, your machine will be running more smoothly all around.
A clean install removes all data in a way, as you format the existing partition to reinstall Mac OS X clean. But if you use the Recovery Partition (see link in post #2), you can do a normal reinstall, not deleting any of your data), but you should probably do a backup before doing so, and then continue backing up, in case of another cock up.
i have reinstalled the Mac OS X and it did not reinstall the English language pack. the problem still persists. Anything other solutions?
Then do a fresh reinstall and have a backup created via Time Machine. So, reformat, reinstall and use TM for recovery. Tip: make a USB installable version of your OS. This can really save your bacon. http://osxdaily.com/2012/07/25/create-os-x-mountain-lion-boot-dvd-usb-drive-liondiskmaker/
Is there any detailed information on how to do this? Like how is the reformat done? And do I need an external hard drive to use Time Capsule?
Yes. How would you be then able to erase your hard drive without losing everything if you were to use the internal drive? Oh, and it's Time Machine, by the way, Time Capsule is a router made by Apple with a hard drive in it.