Of interest perhaps, is a recent study/analysis of why scammers always sound so stupid:

Why Nigerian Scammers Claim to Be From Nigeria

A full analysis (as summarized at the above link) is also at:

Research paper - pdf

(The second link may demand that you run "Zeon" which is a substitute for Adobe's pdf reader. I - and my Norton - have found it safe enough, and probably safer than Adobe(?).)

The full research paper is pretty deep reading, unless you're fluent in linear analysis and statistics, but the first link summarizes pretty well.

John