> Here in the States, it seems to have been eclipsed
> by another constructed language–Klingon.

This is a myth. The number of people who can speak
Klingon fluently is tiny. According to wikipedia…
http://en.wikipedia.org/wiki/Klingon_language
… only 12 people could speak it in 1996 and I
doubt it has changed much. Even Marc Okrand,
the creator of Klingon, does not speak it. The
number of people who speak Esperanto fluently is hard
to assess, but it is in the thousands at least. Wikipedia
http://en.wikipedia.org/wiki/Esperanto_language says
that it might be between 100,000 and 2 million. I think
it’s in the lower range, but in any case, it’s not in the
same league as Klingon. Just compare the content of
Wikipedia in Esperanto and in Klingon. There are also
many blogs entirely in Esperanto, many software
translated in Esperanto, many web sites available
in Esperanto, etc. I’m not aware of anything
equivalent in Klingon. The web site http://www.lernu.net
which is dedicated to teaching Esperanto has over
80,000 registered users. There is quite a fair number
of books also available in Esperanto, but don’t there
is much literature available in Klingon, or at least
not on planet earth Qapla’