In Final Fantasy Tactics, Sylph (also known as Silf) can be learned by the Summoner job and costs 400 JP. Its attack, Whispering Wind, attempts to inflict Silence on all enemies in a large area. It costs 26 MP and has a speed of 20.
In the PlayStation version, when summoned, the summoner will sometimes say, "Show us to put our lives back on track! Silf!"