This study started from the two main problems. Those are (1) the factors caused the shift of Tonsea Language and (2) the factors supported the maintenance of the language. Based on the problems above, this study aimed to find out the factors causing the shift of Tonsea language and the factors supporting the maintenance of the language. As a consequence, the population of this study was all the member of Tonsea speech community, especially the 4.778 persons who lived in the village of Laikit, Dimembe. Then, the respondents of this study were 140 persons, taken through proportional stratified random sampling based on their sex, age, education, and occupation.
in order to obtain such aims the researcher involved the following ways. Data were collected through structured interview, questionnaires, participatory observation, and recording. The questionnaires was given to the respondents who were eleven to eighteen of age and above twenty-one. in addition, the process of recording was aided with some stimulation to the informants. Then, the data were analyzed with ANOVA in order to get the level of significance of their language choice. To make sure the accuracy of the computation the researcher used statistic computer "Microstat".
This study found the following result. Tonsea language was used by the tonsean aged fifty or more as the language was mastered enough by such people. The language was also used as a culture support, such as in family meeting, arisan, wedding ceremony, funeral ceremony, tumuwar activity, and traditional ceremony in order to release a village from the troubles made by devils. in addition, the language was also used by the youth when they were talking to their siblings, brothers or sisters in law, parents, and grand-parents. Malay-Manado language was used among tonseans who were under fifty of age in their community, by tonsean under fifty of age to their children, to their parents, and to the other persons in the same village. Mixed language was used by the participants in the situations other than what is mentioned above. Bahasa Indonesia tend to be used by the youth in educational and religious domain.
The maintenance variables of Tonsea Language were age, education and occupation. The tonseans who were fifty or more tend to maintain the language while those who were under fifty were not. The tonseans whose education was elementary school tend to use Tonsea language while those whose education were high school or university tend to use Malay-lVlenado or mixed the languages. Farmers, housewives, and merchandiser tend to use Tonsea language while civil servants, military member, students, and private servants tend to use Malay-Manado or mix the languages.