[MUSIC] The figure plots, the log of frequency of occurrence of the children speech as a function of the log of the parental input frequency. There's a strong effect of parental input frequency, especially around the age of 2 years and older. The smaller partial correlations before age 2 indicates that some other variables must be influential in vocabulary acquisition. We will now consider those variables. There has been a long tradition in memory research, that words high in concreteness and imageability, are easier to learn and remember. Measures of concreteness and image ability are determined from studies in which adults are asked to rate these variables, usually on a scale from one to seven. It turns out that concreteness and imageability are highly correlated with one another, so it is necessary and sufficient to evaluate just one of these. The figure plots the log frequency of occurrence in the children's speech database, as a function of the imageability ratings. Children tend to say words that are high in imageability, especially in the first years of life. Another possible influence on vocabulary acquisition is articulation difficulty. Some consonants are more difficult to utter than others. For example, M and B are easy to say, whereas R and S are difficult. A word's articulation difficultly was defined by the difficulty of the consonants that make it up. A child's production of words might relate to the difficulty of articulation of segments of the words. We might expect those words easier to articulate, would tend to be produced, and perhaps, understood earlier than those more difficult to articulate. The figure plots log frequency of occurrence in the children speech database as a function of articulation difficulty. Children cannot just say words that are high in articulation difficulty, especially in the first years of life. Investigators have recently proposed that iconicity might be an important variable influencing vocabulary acquisition. We all have heard a rose by any other name would smell as sweet. When Juliet spoke these memorable words in William Shakespeare's play, Romeo and Juliet, she observed that the name Montague didn't dampen her love. Like Juliet, linguists have also proffered the arbitrary relationship between the properties of a word and those of its meaning. In sharp contrast to this tradition however, we can ask to what extent iconicity might exist, at least in the early vocabulary children acquire. Iconicity can be defined as a correspondence between the form of an expression and its meaning. In the present case with spoken language, it would be a cross-modal correspondences between the speech characteristics of a word and the characteristics of the object or event that the speech symbol represents. Adults can be asked to determine the iconicity of specific words. To give you a feel for this task, here are some instructions. Some English words sound like what they mean. For example, slurp sounds like the noise made when you perform this kind of drinking action. Teeny sounds like something very small and huge sounds, very big. These words are iconic. You might be able to guess these words meaning, even if you did not know English. Words can also sound like the opposite of what they mean. For example, microorganism is a large word that means something very small. And whale is a small word that means something very large. And finally, many words are not iconic or opposite at all. For example, there is nothing canine or feline sounding about the words dog or cat. These words are arbitrary. If you did not know English, you would not be able to guess the meanings of these words. Your task is to rate each word on a scale from minus five to plus five, corresponding to the degree of the iconicity of the word. [MUSIC]
