Last Monday I wrote about tone sandhi, the tone changes that may occur when two syllables come together. Another notable aspect of pronunciation is related to the vowel "i". The "normal" way to pronounce this vowel is as the "ee" in e.g. "bee".
However, "i" is also used to stand for what my textbook tells me is called "the blade-palatal vowel [ʅ]" after the initials "ch", "r", "sh", and "zh", and "the blade-alveolar vowel [ɿ]" after the initials "c", "s", and "z". (According to Wikipedia, the "ee" sound I describe in the previous paragraph is a "close front unrounded vowel".)
This takes us into the realm of phonetics, a subject which fascinates and baffles me in equal measures. Although I have spent hours on the internet trying to find some good examples of people pronouncing the various "i"s mentioned above, somehow I always end up going around in circles.
My textbook says: In pronouncing such symbols as "zhi" and "chi", the tongue is kept still, and care must be taken not to pronounce it as the simple final "i[i]" which is never found after "zh, ch, sh" or "r". (It is silent on the matter of pronouncing e.g. "si".) Wikipedia says: -i is a buzzed continuation of the consonant following z-, c-, s-, zh-, ch-, sh- or r-. In the last resort, as a very rough guide, I suppose I'd say that using an "uh" sound for it instead of an "ee" sound would be an improvement.
As I said in my introductory post, I don't actually speak Mandarin, so I don't plan to go much further into its details than this. However, the double third tone sandhi and the different pronunciations of "i" confused me for ages, so I thought it was worth mentioning them.
(Note added later: In comments, pne points out a couple of slightly more subtle pronunciation variations regarding "e" and "u".)