On the subject of the psychology of language development, researchers have been able to show that infants start learning new words before they even begin to speak, as early as 1o months (Pruden, Hirsh-Pasek, Golinkoff, & Hennon, 2006). They can also use words in recognizing complex objects by 12 months (Hollich, Golinkoff, & Hirsh-Pesek, 2007).
This is something to remember when talking to (or around) young ones because they often will understand much, much more than you might expect…
References
Hollich, G., Golinkoff, R. M., & Hirsh-Pasek, K. (2007). Young children associate novel words with complex objects rather than salient parts. Developmental Psychology, 43, 1051-1061.
Pruden, S. M., Hirsh-Pasek, K., Golinkoff, R. M., & Hennon, E. A. (2006). The birth of words: Ten-month-olds learn words through perceptual salience. Child Development, 77, 266-280. [READ THE ARTICLE!]