Dictionaries

[hoagy-davis-digges]

I'm sure this is rather obvious, but I'm new to Vim so please bear with me.

How do I add a dictionary so that it appears automatically like it would if I pressed ?

Also how do I do that for a single session?

[Shougo]

To add dictionaries, you must change dictionary option or g:neocomplcache_dictionary_filetype_lists.

[hoagy-davis-digges]

Is there a command that allows me to do this on the fly, rather than by editing the .vimrc?

Basically I want to use a wordpress dictionary for some of my PHP files, but not all of them, so I would like to be able to activate it occasionally.

[Shougo]

Is there a command that allows me to do this on the fly, rather than by editing the .vimrc?

No. But you can write it.