J´ai trouvé ca sur un site :
The verbal taunt is activated by “spotting” an enemy player who is in a “man down” state (ie dead or critically wounded). The rules for how often it can be used are governed by the servers radio spam settings in the same manner as all player messages.
In order to use the taunt you must have registered for the veterancy program, and have both BF2 and 2142 installed. The actual taunt is a random selection of one of three possible sounds.