RESUMO
<p><b>OBJECTIVE</b>Many researchers have conducted studies on child language development and relevant risk factors, but most of these studies were about English-speaking children and few of them were on Chinese-speaking children, and less reports of studies on language development of infants or toddlers are available as compared to those on children above 3 years of age. The objective of this study was to assess the level of vocabulary development of healthy toddlers in urban Beijing and to investigate toddlers' physical and psychological development and socioeconomic status of toddlers' family so as to identify factors related to toddlers' language development and provide basis for instructing parents child-rearing.</p><p><b>METHOD</b>This is a quantitative cross-sectional study. Using Chinese Communicative Development Inventory mandarin version, (CCDI) and related background questionnaire, a survey was conducted among the parents or care givers of 1056 healthy toddlers (16 approximately 30 months), randomly stratified and selected from two areas of four urban districts in Beijing. The children who were born prematurely, who had low birth weight, or who were deaf, dumb or with disability, were excluded from this study. The mothers who were deaf, dumb or having disability were not included in this study, either. Rank sum test was used to compare the vocabulary scores between boys and girls at the same age. Single and multiple factors analysis were used to find related factors.</p><p><b>RESULTS</b>By 16 months of age, boys could speak about 22 words and girls 84 words on the CCDI. By 29 - 30 months of age, boys could speak about 725 words and girls 752 words on the CCDI. The level of vocabulary development of healthy toddlers in urban Beijing was higher than that reported in previous studies of English-speaking children. Girls had higher vocabulary scores than boys in a few different age groups. Single factor analysis showed that the ages of father and mother, income of father, the language used by care-givers and GDP of the families were factors related to families of toddlers and the age, gender, height, weight and the age at which the toddlers began to speak were factors related to individuals. Multiple factors analysis showed that higher education level of mothers, younger father, earlier beginning of children to speak, toddlers' amiable disposition and emotion, girls, toddlers' age and height positively correlated with toddlers' vocabulary score.</p><p><b>CONCLUSION</b>The level of vocabulary development of healthy toddlers in urban Beijing is on the high side. Certain individual and familial factors may influence toddlers' language development. It is suggested that health workers should pay attention to the toddlers' language development. The toddlers' parents and caregivers should be taught how to interact with and talk to their children and how to promote children to develop healthy disposition and emotion.</p>