What is Manipravalam? Name a book written in that language

What is Manipravalam? Name a book written in that language.

Manipravalam literary means’diamonds and corals’and refers to the two languages Sanskrit and the regional language.
Lilatilakam which deals with grammar and poetics was composed in Manipravalam.

OR
Manipravalam was a literary style that consisted of a mixture of early Malayalam and Sanskrit. The word Manipravalam means diamonds and corals. Malayalam and Sanskrit were the two languages referred to as Manipravalam.