The formal study of language began in India with Pāṇini, the 5th century BC grammarian who formulated 3,959 rules of Sanskrit morphology. Pāṇini’s systematic classification of the sounds of Sanskrit into consonants and vowels, and word classes, such as nouns and verbs, was the first known instance of its kind. In the Middle East Sibawayh (سیبویه) made a detailed description of Arabic in 760 AD in his monumental work, Al-kitab fi al-nahw (الكتاب في النحو, The Book on Grammar), the first known author to distinguish between sounds and phonemes (sounds as units of a linguistic system).

Western interest in the study of languages began as early as in the East,[9] but the grammarians of the classical languages did not use the same methods or reach the same conclusions as their contemporaries in the Indic world. Early interest in language in the West was a part of philosophy, not of grammatical description. The first insights into semantic theory were made by Plato in his Cratylus dialogue, where he argues that words denote concepts that are eternal and exist in the world of ideas. This work is the first to use the word etymology to describe the history of a word's meaning.

Around 280 BC one of Alexander the Great’s successors founded a university (see Musaeum) in Alexandria, where a school of philologists studied the ancient texts in and taught Greek to speakers of other languages. This school was the first to use the word "grammar" in its modern sense, Plato had used the word in its original meaning as "téchnē grammatikḗ" (Τέχνη Γραμματική), the "art of writing," which is also the title of one of the most important works of the Alexandrine school by Dionysius Thrax.[10]

Throughout the Middle Ages the study of language was subsumed under the topic of philology, the study of ancient languages and texts, practiced by such educators as Roger Ascham, Wolfgang Ratke and John Amos Comenius.[11]