* Data Collection Challenges: Accurately collecting data on language proficiency and usage across the globe is incredibly complex. Definitions of "bilingual" vary, and many people may have varying levels of fluency in multiple languages.
* Regional Variations: The prevalence of bilingualism and multilingualism varies greatly depending on location. In countries with high levels of immigration or historical multilingualism (like Switzerland or India), bilingualism is much more common than in countries with a single dominant language (like Japan or Iceland).
* Language Definitions: Even defining "bilingual" is difficult. Some consider anyone who speaks two languages to be bilingual, regardless of fluency level, while others require a higher level of proficiency.
However, based on existing data and estimates:
* Bilingualism is becoming more common: With increased globalization, migration, and exposure to multiple languages, the number of bilingual individuals is likely increasing worldwide.
* Many regions have high levels of bilingualism: In many parts of the world, particularly in Europe, Africa, and Asia, bilingualism is common.
* The majority of the world's population likely speaks multiple languages: While there is no concrete number, it is highly probable that a significant portion of the global population is exposed to and utilizes more than one language.
In conclusion: It is impossible to provide a definitive answer, but the increasing prevalence of bilingualism and the diversity of languages across the globe suggest that a considerable number of people are likely bilingual.