I'm sure there's a name for this phenomenon but I'll be damned if I can find it. I'm sure I read about it somewhere. Maybe in one of this list of articles?

All I could find were references to the 'labialisation' and 'rounding' of the alveolar approximate (English R), or the sound changes caused by alveolar contact with /j/.

http://en.wikipedia.org/wiki/English_Phonology
http://en.wikipedia.org/wiki/Australian_English
http://en.wikipedia.org/wiki/Australian_English_ph...

For me, they’re affricates across the board, but notice one thing: It only works when the two letters are in the same word. “Ed right” does not equal “Edge right”, since the “d” and the “r” are not in the same word.

Similarly, where I live, many (most?) people pronounce [aɪ] like [ʌɪ] before voiceless consonants. Yet when such a thing is across the voice boundary, that doesn’t happen: “Why choose” is [waɪʧuz], but “White shoes” is [wʌɪtˀʃuz]. Sometimes compounds are treated as single words: “high chair” and “high school”, for example, both use [ʌɪ]. And several times the sound occurs before voiced consonants, such as in “cider” and “tiny”.

Thanks for all the feedback. Very thought-provoking and surprising for me. I confess I never would have expected that it would be hard to pronounce "dr/tr" as actual "dr/tr" instead of "ĝr/ĉr" for native English speakers (given that we all can say "t" and "r" quite well as independent sounds - e.g. we all say "tee" as "tee" and not "ĉee", right...? Now I begin to wonder...!

I've never consciously noticed this phenomenon before. Apparently I automatically "translate" it in my mind when I hear it, the same as not consciously worrying about differences between a southern US drawl or NY accent or whatever unless I'm intentionally thinking about them.

I'm saying "tree/ĉree" and the other pairs to myself, and for me there's a clear obvious difference, and I honestly see no difficulty saying dr/tr as actual dr/tr instead of ĝr/ĉr. It's as surprising to me as if native English speakers were telling me "I can't say sp as in speaker, it comes out ŝp!" or something.

I'll be visiting the US in a couple months and will have to be aware and listen for this!