The Problems of the Study The Objectives of the Study

2. Encourage the children to communicate politely and to produce the correct words and if they make mistakes, give the exact words and pronunciations. 3. Inform the parents who worried about children language acquisition in uttering words because they have to know when and what factors can influence the children’s ability to produce words and speech as the anticipation for same parents who worried about their children. 68 REFERENCES Alwi, H., Soenjono Dardjowidjojo, dkk. 2003. Tata Bahasa Baku Bahasa Indonesia. Jakarta: Balai Pustaka. Ardhana W., 1986. Dasar-dasar Kependidikan, FKIP, Malang. Azar, B. Schrampfer, 2001. Basic English Grammar, New Jersey: Person Education Asia. Barret, M.D. 1995. Early Lexical Development. Oxford Blacwell. Biemiller, A., 2009. Teaching Vocabulary: Early, Direct, and Sequential. Essential Readings on Vocabulary Instruction, ed. by Michael F. Graves. International Reading Association. BMA Board of Science, 2006. Child and Adolescent Mental Health: A Guide for Healthcare Professionals. British Medical Association. Boyson-Bardies, B. 1999. How Language Comes to Children. Massachusets: Massachusets Institute of Technology. Chaer, A. 2003. Psikolinguistik; Kajian Teoretik. Jakarta: Rineka Cipta. Clark, E. V. 2003. First Language Acquisition. New York: Stanford University. Crain, S., Diane Lillo-Martin, 1999. An Introduction to Linguistics Theory and Language Acquisition. Massachusetts=Blackwell Publisher Inc. Dale, P. 1972. Language Development: Structure and Function. Illonois: The Dryden Press. Darjowidjojo, S., 2000. ECHA: Kisah Pemerolehan Bahasa Anak Indonesia. Jakarta: Gramedia Widiasarana Indonesia. Dykens, E. M. 2000. Psychopathology in children with intellectual disability. Journal of Child Psychology and Psychiatry, 41, 407-417. Dykens, E. M. Hodapp, R. M., 2001. Research in mental retardation: toward an etiological approach. Journal of Child Psychology and Psychiatry, 42, 49- 71. Einfeld, S. Emerson, E., 2007. Intellectual disability. In Rutter’s Child and Adolescent Psychiatry eds. M. Rutter, D. Bishop, D. Pine, D. Bishop, D. Pine, et al, inpress. Blackwell.