Or ‘see’, but we really don’t have the phoneme in English. Anyway it isn’t ‘she’.

to use a 90-year-old descriptor.

Say "shhhh" in English. It's not Mandarin, it's in between.

Say "she" and "show." In my pronunciation, those two "sh" have a different pitch center. One sounds higher, one sounds lower. A third or so (maybe minor, maybe major).

Now move your tongue so that the hissing sound has an lower pitch, but not too much lower than "shoe" and in my warped speech "shoe" isn't bad for its "sh". In any event, not as low as possible--that pushes towards a weird retroflex "h" sound I don't even know how to search UPSID for. But it's distinctly lower than English "show".

That's Putonghua/Mandarin sh.

Go back to "she" and make that "sh" have an even higher pitch, but not very much. Otherwise we're again in weird-land. That's Putonghua x.

I think of them as parallel to Polish ś vs sz, with parallels in Polish ć vs cz or Croatian ć vs č. Both contrast sharp vs flat.

If you're interested, this is an old distinctive feature that was around for a few decades, so I should be putting [ and ] around them, but that's wonky and I don't wanna. It's been replaced by [ coronal ] (and in some contexts [ dorsal ], depending on the linguist's druthers). But again, I teach high school physical sciences and haven't been a student or scholar of any sort of linguistics for almost 20 years.

I'm learning Mandarin, and these two consonants are different. Moreover, they affect the vowel in their syllable differently: "shi" is more like the English word "ship" and "she" is more like the English word "shed", where "xi" is, I suppose, closest to the English word "she".

However, the pinyin "x" is pronounced with the tongue placed behind the lower front teeth, a consonant English does not have. The Mandarin "sh" also puts the tongue further back on the palette than does English's.

The first alphabets were proposed by missionaries, who typically were familiar with Latin and Italian, often German, French or Portugese as well. The phonemes used in Chinese do not correspond exactly to those used in Western languages, so some of the mapping between Chinese sounds and Roman letters had to be a bit arbitrary. The current system is sort of a hybrid of other systems proposed historically by Westerners and Chinese scholars, revised by native speakers in multiple iterations.

For more, see the Wikipedia entry for Pinyin.

Giles-Wade's on the out, unless you're hard-core Taiwanese. Pinyin's not a bad compromise--it's phonemic, if not phonetic.

Strictly speaking, Pinyin also has tone numbers or diacritics that we conveniently ignore--we want to show sensitivity, with rolled rs and the like, but, you know, sensitivity is local and we don't care about tone and tone sandhi in Chinese languages. We have the ability but not the will to be equitably sensitive. Odd, that.

Recently read that "brainwashing" is a calque from Mandarin xi nao, but that didn't tell me much. After a few minutes noodling/googling, I got x ǐ nǎo, which in my 1st year text was to be realized as [ xí nào ], two words added to my aural/oral vocab but not my written. Oddly, the publication, punctilious in its use of Spanish diacritics and the occasional African-language diacritic, bailed entirely on Mandarin. "Equitable" and "sensitive" apparently involves thinking locally, acting locally. I found the diacritics in a source unusable on DU. (That gives me heartburn.)

(I do draw the line at non-Roman alphabets. I'm okay with some, but there are scores of them. Kufic, sure; Naskh gives me pain; I knew devanagari at one point, but it's gone, while Hebrew, Slavic, most Cyrillic Turkic and even some less frequent Roman varieties are fine, along with Gk, Attic/Byzantine/Modern. Still, I figure I'm a bit of an outlier. But do include the diacritics in transliteration. And diacritics in non-translation.)