Over the years I had collected a number of research articles on antiquity of languages, a topic that interests me. I have place some of them in a dropbox folder, link to which is given below. It might be handy to at least cursorily look at a few of them. You will find several publications which are linguistically based, and thus for a nonspecialist (me included) a bit difficult to understand, but the main arguments, nevertheless, are understandable.
Since the discovery of Sanskrit by the Europeans in the 1700s, it has been an active research area, especially by English and German scholars. Many original articles are in German which I will gladly share once I assemble them into a folder. (I studied German during my college days, and at one point in time was somewhat fluent in it) With Google translator they are far more accessible to us now, of one is willing to put in a bit of work. Fortunately those original treatises have for most part available in English.
Of the articles in dropbox, you may want to first listen to Prof Atkinson's interview and read his research article titled - Mapping the origins and expansion of the Indo-European Language family.It was published last year in Science. (Science and Nature are two world's leading journals where discoveries are reported) The Google books titled Avesta-Sanskrit comparison (grammar and phonology) by Prof Jackson might be interesting for those who know Sanskrit. Prof Jackson (was at Columbia University) drew his inspirations from Prof Gelder's (almost his contemporary) pioneering study in the late 1800s.
For those (such as I) who are light readers, you will find Prof Burrow's publications excellent for introduction to this are of languages. Unfortunately they are not available free, but can be ordered via Amazon (here in the US) and probably via book stores in India. Their proper citations are:
Interestingly, Prof Burrows has published a wonderful Dravidian etymological dictionary (which is useful to find evidences for Shah's observation on Tamil influence on Sanskrit)
A request. The research articles published by journals are subject to copyright restrictions. I am distributing them to this private research group, and thus I am not violating the law. Please do not distribute to folks outside of this Yahoo group, that might be a violation of the law.
Another word of caution- when we deal with anything that is ancient, such as this topic of discussion- we have facts (rare, unfortunately; supported by physical evidences), considered opinions (points of view of scholars based on indirect evidences, and reasonable conjectures), opinions (a point of view without evidences) and finally fiction (an imagination of the opinionator).