Diglossia is essentially a term used to describe a state of the people who know and use two or more languages to communicate among its members (a society that recognized two or more languages for intrasocietal communication). So the use of bilingual diglossia situation or more in the same community 'governed' by a policy for the selection of the language to be use. Event diglossia shows the distribution function of two or more languages are also giving the impression of their kind of language that is "high" and the type of language that is "low", This type of language used is high in situations that are considered more formal, by people including educated, and more prestige value and prestige. While the types of lower language used in situations that are more informal, by the common man and as a means of general intercommunication. In fact, diglossia situation is actually happening in Indonesia; Functions performed by Indonesian high and low functions carried out by the regional languages in Indonesia. National language as a second language that calls for all levels of society to use it, could result in local languages as a first language gradually eroded. If it is forced through, then the language area that is less powerful because it's a little bit unknown can disappear even more in the future. This is certainly very unfortunate, because it coincides with the loss of local languages, indigenous or traditional knowledge stored in the oral tradition also can not be saved. It was when seen from the side of the opposition; Different when seen from the side of the union, then between the local language and national languages can co-exist in harmony. This study wanted to examine the analytic theory of how language Pakpak Dairi sociolinguistic as local and Indonesian language as the national language used by speakers in North Sumatra that suffered disproportionately situation.