1. Diglossia refers to a linguistic situation in which two varieties of a language are used by a community for different purposes or in different contexts. In verbal communication, several aspects of diglossia can come to the surface:

a) Function: The two varieties, often referred to as "high" (H) and "low" (L), have distinct functions. The high variety is typically used in formal settings, such as education, literature, or religious ceremonies, while the low variety is used in informal, everyday interactions.

b) Prestige: The high variety is associated with prestige, power, and higher social status, while the low variety may be perceived as less prestigious or even stigmatized.

c) Context: The choice of variety depends on the social context and the interlocutors. People switch between the high and low varieties based on the formality of the situation and the status of the participants.

d) Competence: Speakers need to be competent in both varieties to navigate different social contexts effectively. The acquisition and maintenance of diglossic competence require exposure and practice in both varieties.

e) Code-switching: Code-switching, the alternation between the high and low varieties within a single conversation or even a sentence, is a common feature of diglossic communication. It serves as a communicative resource for expressing identity, signaling solidarity, or emphasizing certain concepts.

2. The relationship between diglossia and bilingualism is complex and interconnected. Bilingualism refers to the ability of individuals to speak and understand two languages proficiently. In a diglossic context, bilingualism often exists among speakers who are proficient in both the high and low varieties.

Diglossia can influence bilingualism in the following ways:

a) Language separation: Bilingual individuals are familiar with the distinct functions and contexts of both varieties. They develop the ability to differentiate between the high and low varieties and use them appropriately according to the social setting.

b) Language dominance: In a diglossic situation, bilingual individuals may exhibit language dominance, where they are more proficient or more comfortable in one variety over the other. This dominance is often influenced by the prestige and prominence of each variety in society.

c) Code-switching: Bilingual speakers in diglossic communities may frequently code-switch between the high and low varieties, depending on the interlocutors, topic, or social norms. Code-switching becomes a strategic tool to navigate between the two linguistic codes and communicate effectively.

References:

- Ferguson, C. A. (1959). Diglossia. Word, 15(2), 325-340.

- Auer, P. (1998). Code-switching in conversation: Language, interaction and identity. Routledge.

- Grosjean, F. (2010). Bilingual: Life and reality. Harvard University Press.

- Myers-Scotton, C. (2006). Multiple voices: An introduction to bilingualism. Wiley-Blackwell.