I've been reading a paper by the Bulgarian Peter Dobrev on the Basarabi (Murfatlar) proto-Bulgar inscriptions. At one point he seeks to demonstrate the occasional lexical affinity between proto-Bulgar and Celtic by writing that "knith" means "seed, sowing, growth" in "Celtic". Unfortunately he does not specify what he means by "Celtic" (which particular language or period). I've consulted a number of dictionaries and have found nothing of relevance. Could anyone shed any light on this Dobrev claim? (He also states that there are "East Iranic cognates" to "Celtic" "knith" and seems to refer to Pamir area Saka.)