Intro to the Indo-European languages:
The Indo-European languages, also: loanwords
Correction: the Buddhist scripture is called "Tripitaka", not "Tripatika". Sorry. Also, it may be more correct to say that it wasn't really the Scythians that conquered India and Iran, but more like the Proto-Scythians--the ancient Indo-Aryan peoples. It's a very minor distinction, but I think worth mentioning.
Further Reading: http://en.wikipedia.org/wiki/Germanic_substrate_hypothesis . Discusses the ancient words that entered Germanic languages.