The term 'language expert' can be defined as a LINGUIST, which is an 8-letter word. A LINGUIST is someone who specializes in the scientific study of language, including its structure, history, and development. They are experts in the field of linguistics, which is the study of the structure, development, and function of language. Linguists often work in research, teaching, and translation roles. They are also involved in the development of language-related technologies, such as natural language processing and machine translation.