[keyboard_smash]

Yeah, the seventh tone in Guangzhou Cantonese that’s gone in Hong Kong Cantonese is the high-falling tone.

In Guangzhou Cantonese, 衫 (shirt) and 三 (three) are not homophones, but they are in Hong Kong Cantonese. The Jyutping romanization (from the Linguistic Society of Hong Kong) reflects this change in HK Cantonese (saam1), whereas Yale, based on the older pronunciation, could represent the difference in tone (sāam vs sàam).

Interestingly enough, the high-falling tone is still retained in Hong Kong Cantonese for one exceedingly common word, the final particle 㖭 (tim1/tìm)!

[hnfong]

I suspect the difference is more "academic" than otherwise.

It would be interesting to give a Hong-Konger a test with pairs of characters, one of 1st tone and the other 7th tone, and see whether they can guess which is which.

I suspect with minimal training they'd be able to score significantly better than random chance. (Willing to try it out!)

[ngcc_hk]

No need of test and I knew nothing. But I can be sure we hk Cantonese know and immediately hear if the other speak in canton or Malaysia Cantonese very quickly.