No individual has the mental capacity to be fluent in all languages. The number of languages spoken worldwide is incredibly vast, and each language comes with its own complexities, nuances, and cultural context. Achieving fluency in all languages would be an impossible task due to the sheer diversity and number of languages spoken around the globe.
Language fluency requires a deep understanding of grammar, vocabulary, pronunciation, and cultural nuances specific to each language. It also requires regular practice and exposure to the language in various contexts. With thousands of languages spoken across different regions, it's impractical for a single person to master them all.
Even polyglots, individuals who have a talent for learning and using multiple languages, typically focus on a limited number of languages and may not achieve complete fluency in every language they attempt to learn.
The success of a person in terms of language proficiency is usually measured by their ability to effectively communicate and interact within specific linguistic communities. Success in language learning is subjective and depends on personal goals, such as travel, business, cultural appreciation, or academic pursuits.
Language specialists, translators, interpreters, and diplomats often possess advanced language skills in multiple languages, but even they tend to specialize in a particular set of languages rather than attempting to master all languages globally.
In summary, while it's a fascinating idea, the practical challenges and limitations of language acquisition make it impossible for any individual to be truly fluent in all languages. Specialization and focus on specific languages or language families are more realistic and achievable language learning goals.