The most commonly used tool nowadays is the Myers Briggs Personality Type Analysis which is based on Jung's work (in fact it's often called the Jung-Myers Briggs analysis). It divides personality into sixteen basic types - you can find out more here :
http://www.personalitypathways.com/
As far as application to efl is concerned - if you go into Google and type
efl myers briggs you'll get various references, including onefrom
hlt Magazine, which I recommend :
http://www.hltmag.co.uk/nov06/mart04.htm