> It seems that the biggest problem of Esperanto now is the way it treats proper names. Browsing through Eo wikipedia, one notices that there is no system in rendering proper names. Some recieve -o at the end, like Pekino, others don't. Some change -a to -o, others don't, yet some others change -a to -ao (e.g. the river Oka is called Okao, but the river Volga is called Volgo). The names originally ending in -a are especially chaotic (some still write "Volga"). One of the reasons why a standalone modifying particle is better than an ending.
Lots of things in Esperanto have stayed the same for decades, but the
approach to proper names seems to have changed.
The "classic" approach esperantized names either from the pronunciation
(Shakespeare -> Ŝekspiro) or from the [European] spelling (e.g.
"Pekino"). Commonly-used names have retained these forms.
But in recent years there has been a tendency (also occurring in
English) to use "official" or "international" forms or transcriptions of
names. In English "Peking" has given way to "Beijing"; and the names of
many towns and cities in India are getting more "authentic"
This is happening in Esperanto as well. Sometimes it is quite orderly,
as with "Hindujo" becoming "Barato". Other times it is messy. For
example, names of Chinese places and people increasingly come in the
"official" transcription, which is perhaps more recognizable (more
standardised) in writing, but gives you little clue to the pronunciation
unless you make a particular study of it.
Names normally written in Cyrillic transfer much more easily into the
Esperanto alphabet (better than into English) because Esperanto has most
of the necessary phonemes. Consequently there is less tendency to use
"international" transcriptions. If you put names into the Esperanto
alphabet, you might as well go the whole hog and put the -o on as well.
Using Esperanto spelling but not Esperanto endings would be seen by most
people as an error, or at least a missed opportunity.
Wikipedia, mentioned by somebody, is certainly the best place to look in
if you are in search of wayward Esperanto. Remember it is more or less
unmoderated; periodicals and web-pages that have an editor and a house
style will in general be consistent. Even so it is certainly true that
there is inconsistency as to which names are Esperantised and which are
not. In general, the more often names are mentioned, the more likely
they are to be assimilated. Esperanto's aversion to homophones also
helps; if "Wien" in Austria becomes "Vieno", then "Vienne" in France is
best left as is. "Londono" is by default assumed to be in England rather
Volapük had, I think, a special marker to introduce "foreign" words, in
particular unassimilated names, and something of the kind has been
proposed for Esperato. It hasn't caught on, but if people feel the need
it is still there and available.