What is the etymology for やいかに

Question

I would like to know more about the usage and etymology of やいかに

Example sentences:

はたして結果やいかに

運命やいかに

はたして鑑定やいかに

Questions:

1. What is the etymology of the word?
2. I have seen also はいかに used also. Is this a proper, and why is や used instead of は?

Answer 1

As a punishment for being clueless, I've Googled this endlessly.

The や here is a substitute for は. This may be dialectal or from old Japanese. I found an allusion to it in this paper: http://conf.ling.cornell.edu/japanese_historical_linguistics/WAFL%5B1%5D.05-Watanabe-final.pdf

Quote from a footnote:

The particle ya can be used to mark what appears to be a topic in predicative sentences when the predicate itself is a wh-phrase. This use is put aside and must be left to future research.

や also evidently appears as a topic marker in Okinawan.

Anyway, essentially the same phrase occurs with the normal topic marker は：

果たして結果は如何に (hatashite, kekka wa ikani)

So it looks like there is no word "yaikani". It is "kekka", a particle, and "ikani".

"Kekka wa ikani?" is useful by itself. The way I understand it, it literally it seems to mean "About the result, to what extent?" I.e. "To what extent was it effective?" "What is the net result?"

With "Hatashite" it seems to be more emphatic and critical. "In reality, what good was it?" (Seeming to have the connotation: it was not effective).

I think the above addresses your 2 question also. When は appears, it is the standard modern Japanese topic particle.