To bind the standard messages, go to the input tab and hit the speech binder...
To bind your own messages open the console and use the following format:
set input keyname teamsay message
Though you could just as easily do 'preferences' in the console and go to Advanced/Raw Key Binds and do it that way...
or if you're a nutcase like me, you could create some of these key aliases:
snipercommands
set input numpad1 teamsay sniper! left flank|set input numpad2 teamsay sniper! behind|set input numpad3 teamsay sniper! right flank|set input numpad4 teamsay sniper! left side|set input numpad5 teamsay sniper! somewhere!|set input numpad6 teamsay sniper! right side|set input numpad7 teamsay sniper! left front|set input numpad8 teamsay sniper! front|set input numpad9 teamsay sniper! right front
blank
set input numpad1 teamsay |set input numpad2 teamsay |set input numpad3 teamsay |set input numpad4 teamsay |set input numpad5 teamsay |set input numpad6 teamsay |set input numpad7 teamsay |set input numpad8 teamsay |set input numpad9 teamsay
tangocommands
set input numpad1 teamsay enemy! left flank|set input numpad2 teamsay enemy! behind|set input numpad3 teamsay enemy! right flank|set input numpad4 teamsay enemy! left side|set input numpad5 teamsay enemies!|set input numpad6 teamsay enemy! right side|set input numpad7 teamsay enemy! left front|set input numpad8 teamsay enemy! dead ahead|set input numpad9 teamsay enemy! right front
defaultcommands
set input numpad1 teamsay left flank|set input numpad2 teamsay back|set input numpad3 teamsay right flank|set input numpad4 teamsay left|set input numpad5 teamsay hold|set input numpad6 teamsay right|set input numpad7 teamsay left front|set input numpad8 teamsay dead ahead|set input numpad9 teamsay right front
selfcommands
set input numpad1 teamsay covering left flank|set input numpad2 teamsay covering rear|set input numpad3 teamsay covering right flank|set input numpad4 teamsay going left|set input numpad5 teamsay holding|set input numpad6 teamsay going right|set input numpad7 teamsay attacking left|set input numpad8 teamsay moving in|set input numpad9 teamsay attacking right