Multilingualism refers to the ability of an individual to understand, speak, read, or write in more than one language. In cognitive psychology, the structure of multilingualism is examined in terms of how multiple languages are represented, organized, processed, and retrieved within the human cognitive system. Research in learning and memory suggests that multilingual individuals do not store each language in completely isolated mental compartments. Instead, languages share interconnected cognitive networks while maintaining distinct phonological, semantic, syntactic, and lexical representations. The structure of multilingualism involves different levels of language representation. At the conceptual level, meanings and ideas are generally shared across languages. A multilingual person often accesses a common concept regardless of the language being used. For example, the concept of "tree" remains the same whether expressed in English, Hindi, or Spanish. However, each language has its own unique lexical forms, pronunciation patterns, and grammatical structures. Cognitive models propose that words from different languages are linked to a shared conceptual system, allowing efficient switching between languages. One influential explanation is the Revised Hierarchical Model proposed by Kroll and Stewart. According to this model, beginning learners often connect second-language words through their first language before accessing meaning. As proficiency increases, direct links develop between second-language words and conceptual memory. Highly proficient multilinguals can access concepts directly through any of their known languages without depending on translation. The Bilingual Interactive Activation Model further explains how multilingual word recognition occurs. It suggests that lexical items from different languages become