A challenge? You wanna challenge?!?

Well, let's redesign what you just wrote:

infangthief comes from OE. infangenþéof, which gives some credence to the theof spelling, but more to the point, I challenge you to say infangtheof so that it seems different to the "real" word.

Altered spelling, and we're gonna say, according to yer reasoning these be all words:

infangthief komes frum OhEe. infangenþéof, whitch givs som creadince twu thea theof speling, buht moarre twu thea poynt, Iye chalenge ywu twu sae infangtheof soa thatt itt seyms diferent twu thea "reale" wurd.

Gud greefe!
WW

P.S. I only found zurf as an acronym on Onelook.