The document discusses ethnicity, multilingualism, and code-switching. It defines ethnicity as identifying with a group through shared heritage, language, culture, and ancestry. Multilingualism refers to an individual's ability to speak multiple languages. Code-switching occurs when bilingual speakers blend two languages in conversation, such as switching between sentences or inserting words from one language into a sentence in another language. Examples of code-switching in English-Indonesian and Hong Kong Cantonese-English are provided.