<P> Semantics is the study of the meaning of words and phrases . Semantics covers vocabulary, which is affected by SES . Children of high SES have larger expressive vocabularies by the age of 24 months due to more efficient processing of familiar words . By age 3, there are significant differences in the amount of dialogue and vocabulary growth between children of low and high SES . A lack of joint attention in children contributes to poor vocabulary growth when compared to their high SES peers . Joint attention and book reading are important factors that affect children's vocabulary growth . With joint attention, a child and adult can focus on the same object, allowing the child to map out words . For example, a child sees an animal running outside and the mom points to it and says, "Look, a dog ." The child will focus its attention to where its mother is pointing and map the word dog to the pointed animal . Joint attention thus facilitates word learning for children . </P> <P> Syntax refers to the arrangement of words and phrases to form sentences . SES affects the production of sentence structures . Although 22 - to 44 - month - old children's production of simple sentence structures does not vary by SES, low SES does contribute to difficulty with complex sentence structures . Complex sentences include sentences that have more than one verb phrase . An example of a complex sentence is, "I want you to sit there". The emergence of simple sentence structures is seen as a structure that is obligatory in everyday speech . Complex sentence structures are optional and can only be mastered if the environment fosters its development . </P> <P> This lag in the sentence formation abilities of low SES children may be caused by less frequent exposure to complex syntax through parental speech . Low SES parents ask fewer response - coaxing questions of their children which limits the opportunities of these children to practice more complex speech patterns . Instead, these parents give their children more direct orders, which has been found to negatively influence the acquisition of more difficult noun and verb phrases . In contrast, high SES households ask their children broad questions to cultivate speech development . Exposure to more questions positively contributes to children's vocabulary growth and complex noun phrase constructions . </P> <P> Children's grasp of morphology, the study of how words are formed, is affected by SES . Children of high SES have advantages in applying grammatical rules, such as the pluralization of nouns and adjectives compared to children of low SES . Pluralizing nouns consists of understanding that some nouns are regular and - s denotes more than one, but also understanding how to apply different rules to irregular nouns . Learning and understanding how to use plural rules is an important tool in conversation and writing . In order to communicate successfully that there is more than one dog running down the street, an - s must be added to dog . Research also finds that the gap in ability to pluralize nouns and adjectives does not diminish by age or schooling because low SES children's reaction times to pluralize nouns and adjectives do not decrease . ll </P>

All but which of the following is considered a measure of socio-economic status (ses)