An update to dejavu (fonts) made the consonants disappear en masse again.
"pkg delete -f dejavu" fixed it

So that appears to have been the actual problem from here, since I probably won't ever know more about the intricacies of font setup without an easy guide to follow, which I suspect due to different platforms of the fonts, won't ever occur.

Freebsd revamped its ports' font structure this week. Reinstalls fixed that issue (missing consonants).

Appeared an errant italic AND cursive font on some sites. Found a program "font-manager" which previews fonts. Found
the .ttf file and moved it from /root/.fonts

So all solved for now.
Opera 12.16 build 1860 FreeBSD 10-STABLE.

Problem was present in all v10 installs. v10 disk crashed.
backed up using a v9 disk, first upgrading it to v10.
v10 >> not upgrading the OPERA port but all its dependencies,
afaik,
default no-problem scenario working again
[ v7 opera > v 12.16 opera > please restore Presto takk... ]
as long as I do not "officially" attempt to install opera
[the system does not see it as installed, but it is installed,
maybe not converted properly in the v9 > v10 BSD pkg method change]

tl;dr
FIXED for now, on the primary disk, [ please restore PRESTO or
all its features in Otter ... or even source the PRESTO so it can
be forked. Even as shareware which is how I bought it in windows98
v1 era... millions of more customers for the latter I surmise. ]

FreeBSD v9 > v10. Dialogs on the UI are only partly visible during a recent shared library bump.
For instance, I can see this as I type, but the title, of this post, is only
a a a a a E a
which may be the same number of those vowells within it. From here, as I type this, I cannot
see the title which I just typed.
Only occurs on some web pages (debian wiki VS gentoo wiki, for instance)
And in about:config: the items to change are visible, but not the selections,

Font >> one cannot see the old to change to a new, but can type it in without knowing
if the spelling is correct, etc.

If there is a term in about:config (specific item) which applies to the text in the
Opera menu button, "Opera", as well as the text one types into the URL bar (as I type
this, the url is showing as " a " ... then I could maybe change its color
or font type and fix the issue.

Thanks.