Ponca-Pawnee Name Inquiry

[Rankin, Robert L]

Good job on tracking down Meyer.  I'd have suggested Czech since there were so many Czech immigrants (whole villages in a couple of cases apparently) in N.E. and N. Central KS and probably adjacent Nebraska.  Back in the '70's I escorted a visiting prof. from Prague around some of these areas N. of Mayetta, KS collecting Czech names from tombstones.
 
> Although I think Bob is probably right about x being read as [ks], I would like to ask if anyone knows where the x convention for the velar fricative originated. 
 
Yes, I'm pretty sure it IS Greek.  When they ran out of Roman letters for phonetic symbols, they turned to Greek first.  Cyrillic gets it from Greek also, but Cyrillic adopted variants of a couple of Hebrew letters too.
 
Given Jimm's information, I'm wondering of Meyer might have made up his own Pawnee name using his only-partly-correct grammar.
 
Bob