Proto: How One Ancient Language Went GlobalLaura Spinney, William Collins, £10.99AS a student back in the late 1970s, I remember hearing about proto-Indo-European, the language from which most current European and Indian langauges are derived. It was then, and remains, a theoretical construct, as it left no direct traces.Back then, linguists had worked back through extant layers of its many descendants to posit their common ancestor, helped by archaeological evidence.