Getting a better spell checker

Guys I am new to Linux in general and want to know what is the use of the following files-:

/usr/share/dict/words  
/usr/share/dict/words.pre-dictionaries-common

Are they used by the spell checker to find potential typos ?

If so are there any better larger word lists out there ? I am sure there must be a 3rd party list that is better than the lists provided in the stock Debian distros.

If so how do I use them in place of the default word lists ?

Also how can I find out what spell checker I am using on my Debian system ?

If so how do I upgrade to GNU Aspell ? According to its site its suppose to be the best for Linux systems

Hello
Try apt-cache search spell to see what is in the Debian repos. You may have several choices. Also synaptic has a good search facility and will tell you what is installed.

How do I install Aspell as my default spell checker ? Also do I need to meddle with the dictionary files ?