A brief history about language

Diachronic vs. synchronic Study of language

The term diachronic is one of the main temporal dimensions of linguistic investigation introduced by the Swiss linguist Ferdinand de Saussure in which languages are studied from the point of view of their historical development, e.g., the changes which have taken place between old and modern English could be described in phonological, grammatical
and semantic terms.
Comparative philology is a branch of historical linguistic studies. It deals with the comparison of the characteristics of different languages or different states of a language through history. It compares the various forms of related languages and attempts to reconstruct the mother language from which they all developed. It starts with the discovery of the
similarities between ancient Sanskrit and other languages of the Indo European family such as classical Greek and Latin (the emphasis is on language change through history).

Synchronic (non-historical descriptive studies)
In this kind of study, languages are studied at a given time. i,e., one describes a state of the language disregarding whatever
changes might be taking place.

It refers to an approach to linguistic studies in which the forms of one or more languages are investigated at one particular stage of their development. This is the approach followed by modern linguists.

A descriptive linguist is like a photographer who petrifies a group of people in a certain position regardless of what went before and after the taking of the picture.

The differences between a linguist and a language teacher