This qualitative, longitudinal, single-case study analyzes naturalistic interactions in Swedish Sign Language. Multiple interactions took place mainly between a mother and a deaf twin on twelve occasions. The participants’ actions and language structure are examined as the child progressed from ten to forty months of age. The results are presented in three segments: transformations (i.e., types of actions during the sessions); gaze; and structure of utterances. The first segment (when the child was between ten and thirteen months of age) includes mediating utterances that contained a few signs with steady eye contact (i.e., focus on an object with mediating, displaced signing, as from the signer’s perspective). The second segment (when the child was between fifteen and twenty-four months of age) includes flexible eye contact, multiple phrases, and narrative structure. The third segment comprises conversations that include a dynamic visual contact utilizing nonmanual structures. Mediating factors such as simultaneous tactile looking, mediating vision, and mediating triangles, which may be useful for pedagogical purposes, are emphasized.