How do I understand Texan people who talk really FAST... like Boomhauer from King of the Hill...?

The last couple days at work I have had to do conference calls from this guy in Texas and he talks soooo fast... he seriously sounds like Boomhauer from King of the Hill... it's not like I can say 'Can you please talk normal' lol !? But yeah I have no idea what he is saying 80% of the time... and first thing tomorrow morning I have to call him...