Tone sandhi is a phonological change occurring in tonal languages, in which the tones assigned to individual words or morphemes change based on the pronunciation of adjacent words or morphemes.
the original tone for each character is: bù shì (4 4)
After tone sandhi: bú shì (2 4)
Some say that it can be confusing to write it as if it is written, it would be confusing to know what the original tone is supposed to be.
Is there an standard practice to address this?