LANGUAGE
     Barton and Tomasello's study (as cited in Berk, 1997), found that mother-toddler-sibling interactions seems to offer a unique context for enhancing the pragmatics of language.  When all three interacted together, conversations almost tripled in length, and each participant took more turns.  Pine's study (as cited in Berk,1997) said that as toddlers listen to the conversations of others, they are exposed to many models and certain skills, such as the use of personal pronouns ("I" versus "you"), which are more common in the first 50 to 100 words of younger than older siblings.