While 其中 is a grammatical function word, its frequent use reflects a preference in Chinese for clear, logical topic-comment sentence structures. The pattern is often to first establish the “topic” (the larger group) and then “comment” on it (provide specific details about a part of it), with 其中 acting as the pivot. In English, we often use relative clauses with “which” or “whom,” for example: “The team has ten members, of whom three are new.” Chinese uses 其中 to achieve the same sophisticated, structured effect in a very neat and compact way: “这个队有十个成员，其中三名是新人。” (zhège duì yǒu shí gè chéngyuán, qízhōng sān míng shì xīnrén). This structure values establishing context before providing details, a common feature in Chinese communication that prioritizes a shared understanding of the overall situation before delving into specifics. Using 其中 correctly demonstrates a higher level of linguistic proficiency and logical thinking.
其中 is most common in written Chinese and formal speech, such as news reports, academic writing, business presentations, and official documents. It's less common in very casual, spoken conversations, where simpler alternatives might be used. The fundamental structure is always: [Group of items/people/reasons], 其中 [comment about a part of the group].
Its connotation is neutral; it is a functional word used for logical connection and clarification.