> The main problem for the martyrs trying to speak Lithuanian is
> diphtongs "ie" and "uo". "Ei" (like in "Maine") and "ou" (like
> in "row) are frequent in other languages but "ie" and "uo" aren't.
> This is one of the reasons I'll have to think about transcribing my
> own name into something more international if I'm planning to do
> anything abroad.

So called 'raising diphtongs' (with the glide coming first) are not so
uncommon (even some Russian dialects have diphtong very close to Lith. uo in
the place of so called 'o under Slavic new acute' and in some other
positions; so a Russian from Riazan' would have no problem rendering your
name, the pitch accent being an important reservation :) ).

> And the third thing that makes it possible to recognize a non-native
> speaker of Lithuanian, including the Russians who have lived for a
> whole decade in the strictly Lithuanian environment is intonation.
> I'm referring to the accentological meaning of "intonation" (okay,
> frankly, I don't know what is the exact English term:). Let me
> explain it: you got a diphtong, say, "ay". You can stress the first
> part of it and this could be called "rising intonation" ("Ay" -
> "Maine"), marked with an accute sign. Alternatively, you can stress
> the second part of the diphtong and that would be "falling
> intonation" ("aY" - I can't think of an example in English right
> now), marked with a circumflex.

Still those Russians who's born here in LT have a chance to try hard and
lose their accent :)
As for me, I have no problem with diphthongs and diphthongic pairs; as for
long vowels, even some native speakers have neutralized acute-circumflex
opposition with y (long i) and U (long u).
An important thing you didn't mention (because of the naturality of such
thing for a native speaker) is the positional change of the QUALITY of a
diphthong's kernel, wich is common in todays standard Lithuaninan in not
mentioned in classical works on Lithuanian phonetics. In aI in laIkas 'time'
(circumflex, raising intonation) a has a strong ae-ish flavour (being
assimilated by mopre prominent glide i), cf. Ai in kAimas 'village' (acute,
falling intonation) where a doesn't undergo any change. The same for eI in
peIlis 'knife' (e becomes close being assimilated by i), cf Ei in lEisti 'to
let', aU in laUkas 'field' (a with o-ish flavour, being assimilated by u),
cf. lAukti 'to wait', iaU in siaUbas 'nightmare' (ia having oe-ish flavour).
For diphthongic pairs, we have OPEN:CLOSED opposition: cf. close (and,
therefore, a liitle o-ish) a in vaRnas 'raven' and open a in vArna 'crow'
(thus giving us an example of IE male chauvinism, as the o: of the second
form shows it's derived nature), the same for aL:Al,aN:An,eR:Er etc.
It should be noticed that Lithuanian dialects also have two additional
accents (see Zinkevicius works on that point, I may provide with a
drill-down those who's interested).

Hope this helps.