I tried flashing the kernel for Fanoush's speed hack but I don't notice any speed improvement. (Apparently if you have it installed right the line that goes across the screen on boot is supposed to make it only half way across before the unit continues its boot cycle and the screen changes (roughly half as long).)

I am using a 1 gig Kingston card; does Fanoush's speed hack only work for 2 gig cards? I ask this because the hacked kernel has "2 gb" right in its name, but I couldn't find any info on whether or not this excludes 1 gb cards. Otherwise I don't know what went wrong. It seemed to install correctly except the flasher script gave me a couple of errors regarding flash_eraseall and nandwrite, but I don't think these were fatal errors (?) I wonder what's going on. Any ideas?

Also, does anyone know where the file lives which has the words for automatic word completion for the software keyboard? I'd like to edit it to add more words that I use frequently.

on my n800 they are in this folder:
/home/user/.osso/hildon-input-method/

.blacklist.dictionary
.personal.dictionary
.used.dictionary

I believe the 'personal' one contains the words the user adds from the keyboard & is probably the one you need. The 'blacklist' probably contains the words that the user deletes via the keyboard. I don't know where the underlying dictionaries are.
These are binary files and I don't know what binary editor might be available under maemo to edit/add words to the '.personal.dictionary' file.

If your device its running then those errors were indeed not fatal but maybe nothing was flashed. If you tried it in hacker edition then redownload flasher and try again. There was a fix week or two ago related to flashing kernel in hacker edition (flasher thinks it runs on n800 so flashing fails to do anything).