The work presented here represents one of the first steps in a research program called "Extended Sanskrit Grammar” and carried out by Jean-Luc Chevillard (CNRS, Paris), Vincenzo Vergiani (Cambridge University) and me. The aim is to study the way in which descriptive models elaborated for Sanskrit have been used to describe other languages, as for instance Tamil, Telugu, Malayalam, etc. This paper focuses on the oldest known grammatical observations from Kerala which are found in a poetical treatise of the 14th century, the Lîlâtilakam, and which provide a good example of "Extended Sanskrit Grammar".