The document discusses various topics related to bilingualism including diglossia, borrowing, code-switching, and code-mixing. It provides definitions and examples of these concepts. Diglossia refers to a situation where two languages or varieties are used in a community, with one having higher status. Borrowing occurs when words are adopted from one language into another due to language contact. Code-switching involves alternating between two languages in conversation, while code-mixing combines words from different languages.