By adrian.peel@iliffemedia.co.uk (Adrian Peel) It has baffled scholars since the 5th century BC, but now a University of Cambridge PhD student has cracked an ancient grammatical puzzle that could “revolutionise the study of Sanskrit” Rishi Rajpopat, an Indian student at St John’s College, made the breakthrough by decoding a rule taught by ‘the father of linguistics’, Pāṇini. The discovery makes it possible to ‘derive’ any Sanskrit word – enabling the construction of millions of grammatically correct words including ‘mantra’ and ‘guru’ – using Pāṇini’s revered ‘language machine’, which is consi…