Tips for pronouncing X vs SH in Mandarin? I'd like to think my Mandarin pronunciation is generally pretty reasonable, but I often get tripped up with X and SH - for example words like 雪 and 水, or 虾 and 莎. Even with different tones, I find these kind of tricky to get right - although obviously context makes the meaning more obvious.

Does anyone have a good tip on how to clearly show the difference in the X sound vs the SH sound? What shape should I have my mouth, and where should I put my tongue for each of these sounds?&nbsp;
'x' is an alveolo-palatal fricative, while 'sh' is a retroflex fricative.

For retroflex 'sh', the tip of the tongue is curled up toward the roof of the mouth while the tongue body is low.
Mandarin 'sh' could be similar to Russian 'ш'.  Start with this wikipedia image of a retroflex stop, but make a slight space for air to pass above the tongue:



For alveolo-palatal 'x', the blade of the tongue approximates the palate while the tongue tip is low.  Mandarin 'x' could be similar to Portuguese or Catalan 'x'.  It can help to press the tongue tip against the lower teeth when learning to pronounce 'x'---this doesn't change the sound, it just keeps your tongue tip out of the way:



More details: Chinese phonology on wikipedia