Any evidence of using signs increasing or decreasing language development?
Gongora X, Farkas C. Infant sign language program effects on synchronic mother-infant interactions. Infant Behav Dev. 2009;32(2):216-25.
Vallotten. Do infants influence their quality of care? Infants’ communicative gestures predict caregivers’ responsiveness. Infant Behav Dev. 2009;32:351-365.