Research shows that one of the most prominent characteristics of infant directed speech is the wider opening of the mouth that is present in those using infant directed speech versus adult directed speech This differences occurs especially in vowels Vocal pitch is also heightened during infant directed speech and research indicates vowels are spoken with the highest pitch when infant directed speech is used The horizontal positioning of the lips in infant directed speech does not differ significantly from positioning used in adult directed speech Instead the only observed difference remains in vertical lip positioning By making the opening of the lips larger infants are more likely to focus on the face of the speaker Research suggests that the larger the opening of the lips during infant directed speech the better infants will understand the message being conveyed due to the additional visual cues available The intensity of speech however does not differ from that used in adult directed speech contrary to popular belief Infant directed speech does not only include the characteristics of high pitched speech and elongated syllables but also incorporates visual body movements that assist in conveying meaning of language to infants One monumental visual aspect of infant directed speech is the movement of the lips In addition head movements are used to emphasize various syllables within language production These visual cues provide infants the additional information needed to perform accurate speech discrimination during language development Further visual cues allow infants to discriminate speech differences in environments in which they can not rely on their hearing such as in noisy environments The auditory and visual aspects of infant directed speech do not exist independently however Infants rely equally on both methods of understanding and as development continues infants strengthen the link between these two important categories It must be considered that although infant directed speech features marked characteristics it may not only be these characteristics aiding in development of language for children Due to the visual cues used by caregivers in this method of communication infants are more highly motivated to engage in communication Because infants are willing to participate in this process caregivers are able to make significant progress through the use of infant directed speech It is often assumed that infants are interested in the properties of infant directed speech and play a passive role in this interaction However research indicates that infants are not only attracted to the practice itself but to people who engage in infant directed speech Through this practice infants are able to determine who positive and encouraging caregivers will be in their development When infants use infant directed speech as a determinant of acceptable caregivers their cognitive development seems to thrive because they are being encouraged by adults who are invested in the development of the given infants