BOSTON — Kawhi Leonard talks now. He talks to the coaches after timeouts and before the huddle. He talks to his teammates on the court, many of whom are new to San Antonio and the Spurs way of doing things. He talks on the plane and he talks in the locker room, making a point of being available to answer postgame questions. Leonard has emerged this season a team leader. Of all the many internal developments that are taking place within the Spurs ecosystem, this may be the most important. “He’s not just doing it by example anymore,” Spurs guard Danny Green told me. “He’s leading by action.” This may not seem like a natural fit for player who is shy to the point of reticence, but it is a necessary one now that Tim Duncan has retired. The way Leonard sees it, he has the experience to voice his opinion. “Definitely, I want to be vocal,” he said. “If I see something they’re doing right, if I see something they’re doing wrong, I just want to point that out and keep getting better.” His methods are suitably subtle: a small conversation about proper spacing here, a note about pick-and-roll coverages there. Leonard is not demonstrative, flashy, or given to anything that would be in any way considered an antic. And that’s perfectly fine for the Spurs who were defined for two decades by Duncan’s steady, reserved persona.