I know that sh, ch, and j are pronounced differently in Chinese than in English, but what about Japanese? I have read that し, ち, じ are pronounced slightly differently than they would be in English (she, chea[p], gee), however I'm never told how. If they (し, ち, じ) are pronounced differently than they would be generally pronounced in English, how?
With the English sounds sh, j and ch, the friction occurs between the alveolar ridge (where the flat part of the mouth located behind the teeth sharply moves up to the palate) and the tip of the tongue. Sometimes, the tongue is a bit further back or curled, and the back part of the tip of the tongue is involved (ie. it is retroflex).
In Japanese, the tip of the tongue is not used for these sounds; instead, a more posterior and wider part of the tongue is used at the point of friction, the tip of the tongue being more or less at the intersection of the bottom teeth and the gum, but without pressing against them.
Are you talking about xi- and qi-? They would be read shi- and chi- by an English speaker. The corresponding kana in Japanese would be si- and ti-. There is no "see" or "tee" sound in original Japanese. Instead they are prounounced shi and chi
hiragana - romanization - IPA - Polish - another language
し - shi - [ɕi] - si [śi] 'sikorka' tit - Chinase: Xi (like in '西安' Xi’an) (sh - German, like in 'ich' I)
ち - chi - [t͡ɕi] - ci [ći] (cisza silence - - (ch - chinase: j as in 豬 pig)
じ - ji - [dʑi] - dzi [dźi] 'dziwny' strange - Chinase: ji (like in 日 sun)
し - 四国 shikoku Shikoku
ち - ちび chibi little
じ - 自転車 jitensha bicycle