Rewrite the essay below to make it more academic, it is a bibliographic concept explanation essay so please do not add subjective opinions
Essay:
Bilingualism can be defined as the use of two or more languages by a person or a community (Swann 27). However, disagreement persists on the extent and nature of language competence involved in the term. While Strazny defines it as broadly encompassing the ability to “read, write, comprehend, or speak” two or more languages to any capacity (140), Bussmann imposes more stringent requirements in his assertion that only those with comparable passive and active proficiency in both languages can be considered “genuine” bilinguals, even going beyond skill by proposing the necessity of regular practice of the languages in “everyday communication” for bilingual status to be conferred (52). 

Within the field, a distinction is moreover made between individual and societal bilingualism. Bussman defines individual bilingualism as “a speaker’s competence in two or more languages and their use in everyday communication” (52), while the definition of societal bilingualism is the existence of two or more languages within a society. Swann further reinforced the definitions by explaining that individual bilingualism does not necessitate the speaker to live in a multilingual society, while societal bilingualism does not require all of its members to use more than one language (27).

Within bilingualism, there is some variation that stems from how the bilingual speakers acquired and learned the languages and how often they use them (Strazny 140). Bilingual speakers typically have one dominant language, which means that they have greater proficiency in it (Strazny 140). The dominant language may also be the native language. "Balanced bilinguals" refer to people who are equally skilled in both languages, while people who acquire two languages at the same time, usually from birth, are called "compound bilinguals" (Strazny 140). Those who learned the second language in a distinct setting, such as a different nation, are named "coordinate bilinguals" (Strazny 140). Strazny stated that in some circumstances, there is a phenomenon labelled "subtractive" when a person's second language occasionally becomes their dominant language and takes the place of their first language (140). This can be a result of people using their second language more and their native language less (Strazny 140).

How the use of two or more languages occurs is also a key component in conceptualising bilingualism. Bilinguals are said to have the propensity of code-switching, a common phenomenon that is defined by blending languages within a statement and topics. Whether a bilingual person will improve their learning attrition is controversial and therefore aroused concerns. Bilinguals are more cognitively and mentally flexible, better at interactive skills and capabilities than monolinguals. However, they may not be able to be proficient in any single language when compared to monolinguals (Strazny 140). Whether only bilingual but not monolingual societies exist in the world is also arguable. Scholars argue that no modern society is monolingual (Swann 27) but others proposed the exception of diglossia, citing that speakers using two functionally different varieties of the same language should be monolingual.