Throughout human history, understanding the fundamental nature of language has been a central concern of scholars and thinkers. Although substantial progress has been made in many areas of linguistics, a precise definition of language remains elusive. This study introduces new insights into the understanding of language and precisely describes its true nature. It formulates a simple universal model of language by applying a newly discovered law–the law of a trio linking thought, language, and reality. The study also illustrates how the law and model can be applied to address important linguistic issues, including the language skills, the universality of languages, the syntactic structure of complex sentences, and the acquisition of first and second languages. The identification of a triadic relationship linking thought, language, and reality is expected to resolve the conflicts between different theories of language, often referred to as theories of meaning. This discovery is expected to elevate linguistics to the same status as the natural sciences for the first time in its history.