istephenyu8790-san, videovillain-san,
wow, very academic thread here
As far as I'm concerned, the /ch/ is pretty same in English and Japanese, which means
even if you pronounce it slightly differently, no native Japanese would even realise
it's a different sound.
I think all those /ch/ sounds used in Japanese can also be changed depending on "where" this
sound comes and what vowel it takes. For example, I'm pretty sure "chu" would sound very different
for your ears if you hear Japanese ones as in "chuui" (= caution). This gets /ch/ gets influence from
Japanese [u] which is different from English one as well.
If you want to make your pronunciation perfect as written in books, the best you can do
would not just see the simbol in IPA, but understand the name for the sound/simbol because
that is what tells us (exactly) how to pronounce and I reckon it's more important to remember.
For instance,
[ʧ]: voiceless palato-alveolar affricate 無声後部歯茎破擦音(むせいこうぶしけいはさつおん)
[t͡ɕ]: voiceless alveolo-palatal affricate 無声歯茎硬口蓋破擦音(むせいしけいこうこうがいはさつおん)
As you see, both are "voiceless affricate" sounds and the slight difference is the point where you make this
sound, but both are near alveolar. From my experiences, unless you have both sounds in one language (which
is your mother tongue), no one can really hear such difference.
Hope this helps.
Natsuko(奈津子),
Team JapanesePod101.com