Introduction, Sources & Citations
Introduction
The period from 12 to 18 months represents one of the most remarkable transformations in human development, marked by the emergence of true language and an unprecedented drive toward independence. During these six crucial months, toddlers typically progress from saying their first recognizable words to developing a vocabulary of 50 or more words, while simultaneously asserting their autonomy through increased mobility, self-help skills, and the famous “no” phase.
This chapter provides comprehensive, evidence-based guidance for understanding and supporting development during this dynamic period. The content is organized into two key developmental phases: 12-15 months (First Words and Early Independence) and 15-18 months (Vocabulary Explosion and Assertive Autonomy), reflecting the natural progression of language and independence skills during this transformative time.
Understanding the interconnected nature of language development and independence is crucial, as these areas support and reinforce each other throughout this period. The emerging ability to communicate needs and desires verbally directly supports a toddler’s growing independence, while increased autonomy provides rich contexts for language learning and practice.
References
Adolph, K. E., & Berger, S. E. (2006). Motor development. In D. Kuhn & R. S. Siegler (Eds.), Handbook of child psychology: Vol. 2. Cognition, perception, and language (6th ed., pp. 161-213). John Wiley & Sons.
Bauer, P. J. (2007). Remembering the times of our lives: Memory in infancy and beyond. Lawrence Erlbaum Associates.
Dunn, J. (2004). Children’s friendships: The beginnings of intimacy. Blackwell Publishing.
Erikson, E. H. (1950). Childhood and society. Norton.
Fenson, L., Dale, P. S., Reznick, J. S., Bates, E., Thal, D. J., Pethick, S. J., … & Stiles, J. (1994). Variability in early communicative development. Monographs of the Society for Research in Child Development, 59(5), 1-173.
Mandler, J. M. (2004). The foundations of mind: Origins of conceptual thought. Oxford University Press.
McMurray, B. (2007). Defusing the childhood vocabulary explosion. Science, 317(5838), 631.
Petitto, L. A., & Holowka, S. (2002). Evaluating attributions of delay and confusion in young bilinguals: Special insights from infants acquiring a signed and spoken language. Sign Language Studies, 3(1), 4-33.
Rescorla, L. (2009). Age 17 language and reading outcomes in late-talking toddlers: Support for a dimensional perspective on language delay. Journal of Speech, Language, and Hearing Research, 52(1), 16-30.
Thompson, R. A. (2006). The development of the person: Social understanding, relationships, conscience, self. In N. Eisenberg, W. Damon, & R. M. Lerner (Eds.), Handbook of child psychology: Vol. 3, Social, emotional, and personality development (6th ed., pp. 24-98). John Wiley & Sons.
Whitehurst, G. J., & Lonigan, C. J. (1998). Child development and emergent literacy. Child Development, 69(3), 848-872.
World Health Organization. (2006). WHO Child Growth Standards: Length/height-for-age, weight-for-age, weight-for-length, weight-for-height and body mass index-for-age: Methods and development. World Health Organization.
