This book investigates the linguistic function and cross-linguistic variation of copulas to determine if they are truly semantically empty elements or essential components of lexical categorization. Dr. Regina Pustet, a scholar in linguistic typology, utilizes a vast dataset of over 160 languages to challenge the traditional view that copulas serve only as syntactic glue. She argues that the presence, absence, or multiplicity of copulas in a language is deeply tied to how that language categorizes lexical items and structures its syntax, providing a new framework for understanding grammaticalization.

Linguists and typologists recognize this work as a significant contribution to the study of grammaticalization and syntactic theory. Readers frequently note the academic density of the prose, which makes it a foundational text for advanced students and researchers in linguistic typology.