The natural soundscape in National Parks is degraded by the intrusion of human-made noises. One usually thinks of the intrusive sounds as those from mechanical devices: aircraft, snowmobiles, off-highway vehicles, tour buses, generators, etc. Noise Model Simulation (NMSim) developed for the Park Service was designed to address those sources. There is, however, often a significant nonmechanical human noise source: the humans themselves. Visitors traveling in groups tend to talk to each other, and that speech can be an intrusive noise source. Newman et al. conducted a listening exercise in Muir Woods National Monument in 2005 to assess the nature of these human sounds. In the fall of 2006 Lawson et al. conducted noise and trail use monitoring in the Great Smoky Mountains National Park, which quantified visitor-generated sound levels and provided input to trail use modeling. Those data provide inputs to NMSim, so that the exposure of visitors to visitor noise and the impact of visitor noise on the soundscape can be quantified. The Smokies study will lead to a general merger of noise and trail use modeling, so there will be tools for this aspect of soundscape modeling and preservation in National Parks.