The study asked whether Deaf mothers seek to exploit the iconicity in signed languages to facilitate their infants' word learning. Two longitudinal case studies followed modifications that 2 Deaf mothers applied to their input while interacting with their hearing infants. Both mothers were sensitive to the communicative abilities of their infants in different periods of language acquisition, and adapted their inputs accordingly. In the prelinguistic period, infant-directed input was characterized by repetitiveness to facilitate the infant's visual perception. During the mid-one-word period, the mothers used exaggerated iconic productions to promote form-meaning mapping. During early syntax development they used adultlike directed signing, applying phonetic reduction modifications to ease and speed up signing. The results support the hypothesis that iconicity plays a role in signed language development and that, in general, modifications act as scaffolding for language learning.