Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context. The earliest known activities in descriptive linguistics have been attributed to Pāṇini around 500 BCE, with his analysis of Sanskrit in Ashtadhyayi. The first subfield of linguistics is the study of language structure, or grammar. This focuses on the system of rules followed by the users of a language.