Eastwards or Westwards

Westwards                                   Eastwards
Out of India Theory                      Indo- Aryan Invasion
Through the Silk Roads there has been a two way travel between East and West for Millennia. Even so  claims about a uni--directional cultural expansion are intertwined with theories of races and sometimes racism. A Westwards approach, which fits with the evidence of Zoroastroanism, Yezidis etc. is associated with an out of India Theory. Meanwhile the Eastwards approach is linked with theories of an Indo-Aryan Invasion.
Some scholars have used the examples of Brahmi and/or Karoshthi to claim that these languages came from the West via (Imperial) Aramaic. There are two fundamental flaws in this claim.
First, early Western alphabets have 22 and subsequently 24, 27 or 28 letters. Sanskrit has 25 basic consonants in a system that has 6 alphabets of 25, 36, 49, 64, 81, 297 etc. letters. How could alphabets of 22 letters provide a framework for complex alphabets with up to ten times the number of letters? Indeed a careful comparison of one version of 31 Letters of Karoshthi reveals a systematic use of the Sanskrit Vargas in structuring the alphabet, e.g. kavarga, cavarga, Tavarga etc.
In the case of brahmi one schoar has focussed on 10 Letters of Brahmi (q.v.) to show parallels between Western alphabets and Brahmi. On closer inspection we find that these seemingly random letters are in fact related closely to the major divisions of Sanskrit which entails 25 consonants in its simple version.
Second, connected with this is a chronological reality. The earliest documented texts in Hebrew are said to go back to the 10th century B.C. and the Hebrew Old Testament describes events which imply a creation of the world in 4004 B.C. The earliest claims for Brahmi script go back to 4067 B.C., i.e. 53 years before the creation and Adam. The Byzantine tradition links creation and the Adamic alphabet with the year 5009 B.C. which is 1004 years before the Hebrew Creation. Georgian sources claim dates for a first alphabet over 6000 B.C. and Macedonians over 7000 B.C. The latest archaeological finds date high civilization in Arbila (Iraq) back to 148,000 B.C. All these peoples clearly did not wait for light from India before speaking. Clearly they developed their own languages. Even so, evidence of early systematic treatment of alphabets and language is clearest in India, which also produced a system that inspired the two main Japanese systems. 
Meanwhile, the Irish Bardic tradition points to links with Iran and ultimately with Taprobane (Ceylon).