After having trouble displaying apostrophe and hyphen in recent
posts  on several lists, I've found that it is not "xterm -u8" or
uxterm which  are intrinsically deficient, but rather it is my "-fn
10x20" option which  is selecting a font size which presumably
lacks  an adequate utf8  character set. I.e., without the fontsize
option, the problem
  characters display OK.

The reason for that option is that even selecting "Huge" at
Ctrl-Right_Click gives an unreadably small font size.
Does anyone know of a substantial fontsize with a more complete  utf8
character set, or a howto on exploring installed X11 fonts and
  their size and unicode characteristics?
Here, fc-list lists many fonts, without any useful size clues, and 
"fc-match utf8" shows only one font:
DejaVuSansttf: "DejaVu Sans" "Book"
And "xlsfonts | grep utf8" returns nothing.

And "xset q" shows: Font Path:
 
/usr/share/fonts/X11/misc,/usr/share/fonts/X11/100dpi/:unscaled,/usr/share/fonts/X11/75dpi/:unscaled,/usr/share/fonts/X11/Type1,/usr/share/fonts/X11/100dpi,/usr/share/fonts/X11/75dpi,built-ins

Any thoughts on whether:  console-setup - console font and keymap
setup program  might help?

Of the squillion font packages available, would there  be mileage in
installing perhaps the first of:
$ apt-cache search font | grep font | grep unicode | more
fonts-cmu - sets the computer modern unicode fonts
fonts-georgewilliams - Free unicode TrueType fonts by George Williams
fonts-junicode - Unicode font for medievalists (Latin, IPA and Runic)
fonts-lg-aboriginal - unicode fonts for North-American Aboriginal
languages
fonts-oflb-euterpe - unicode musical font
fonts-senamirmir-washra - collection of unicode fonts for the Ethiopic
script
xfonts-efont-unicode - /efont/ Unicode fonts for X which cover various
scripts
xfonts-efont-unicode-ib - /efont/ Unicode fonts for X (italic and bold
But what then? Any firm ground in this swamp would help a lot while
I  work on building taller stilts. Google hits thus far furnish
little or no  additional stuff to check or implement.

Erik