At a rough estimate; 40% Latin, 25% Greek, 15% Proto-Indo European, 10% Sanskrit/Proto-Semitic

The Greek language is believed to have evolved from an earlier language known as Proto-Greek, which was spoken around 2,000-3,000 BC. It is difficult to attribute the invention of the Greek language to a single individual, as it developed over time through a process of linguistic evolution and interaction with other languages in the region.

No, but it is an area of research within linguistics. The reconstructed Language is called Proto-Human or Proto-World.

There is no Proto-Indo-European language group. Proto-Indo-European, or PIE, is the hypothetical root language from which Indo-European languages today (and others that are extinct) descend.

The classical Greek, and New Testament word is "proton", also the use of "proto" is traced to this word. A proto-type, or first-type.