This is a corpus driven study with an aim to assess and describe the oral skills in practical settings of primary and secondary school students in Xiamen. Based on literature review of previous studies on oral proficiency carried out by both Chinese and international researchers, three indicators of vocabulary, grammar and rhetorics are selected and quantified for evaluation purposes. To find out the developing patterns of oral skills, comparison is made across different grades and schools located in different areas. The findings show gradual development features in oral proficiency development, that is, their oral proficiency develops along with ages, cognition and schooling years when they go from lower grades to higher grades, and the development is demonstrated in all three indicators of vocabulary size, grammatical competence and the application of rhetorical devices. In other words, the developing scale for secondary students advances faster than their primary counterparts in all three indexes.Geographically, the performance of students living in urban districts shows stronger than those living in small towns and rural areas, including such aspects as expression strategy and willingness to communicate. Due to the lower motivation in willingness to communicate, fewer grammatical problems were observed among the students from rural and small town schools. Based on the empirical evidence, two suggestions are proposed: first, the training of speaking proficiency should distinguish the surface and the deep layers, whereas the former refers to linguistic forms such as vocabulary and syntax, the latter is about semantics; second, there is a need to establish both core quantitative criteria and auxiliary criteria.