Although evidence is available about preterm newborns' spontaneous behavioral repertoire during the first weeks of life in the neonatal intensive care unit (NICU), studies on infant behavioral responses to external social stimuli are scarce. The main aim of this study was to analyze preterm infant behaviors in response to the maternal voice, speaking or singing, in the NICU, compared with a control condition when the mother was not present. We hypothesized that the infants' self-touch, eye-opening, and oral behaviors would increase in the singing and speaking conditions. The neonates' behavior was video recorded and then coded by using the System for Coding Perinatal Behavior. Preterm newborns showed increased self-touch and eye-opening behaviors during maternal-directed speech and songs in the NICU. Oral movements were modulated differently by the singing and speaking conditions: the singing condition was specifically associated with infants' rhythmical sucking behaviors and smiles, whereas maternal speech was associated with non-rhythmical mouth movements. In both speaking and singing conditions, yawning occurred more frequently than in the control condition. The findings of this pilot study suggest that preterm newborns from 32 weeks' postmenstrual age respond to social and contingent stimuli with a general activation of self-touch and eye-opening behaviors. However, they respond to live maternal speech versus songs by showing different oral behaviors. The differential responses and clinical implications of the findings are discussed.