While I feel my pronunciation is getting slightly better (reports on it from the girlfriend have gone from being "OMG it hurts, stop trying to speak our language!" to "You sound like a Chinese trying to speak Vietnamese"), there are still a few sounds that throw me off, none more annoying than C and G. When I'm speaking, con cá and ga con tend to sound like the same word, just reversed. Likewise, with gam ơn sometimes it seems like she's telling me the first part should sound more like "come", other times it sounds like she wants it to sound more like "gum".

I guess part of the confusion might also be from the fact that while everyone I know who speaks Vietnamese speaks the southern dialect, all of the resources I have been able to find (and therefore learning from) only use the northern dialect, which I already know has a number of phonological differences, so sometimes I switch a bit randomly (e.g. con rươi ="kohn zoo-oi", whereas ao dai = "ao yai").

Help?