‘cing3’ is the only legitimate reading for 秤. There is no variant reading in 廣州話正音字典 (p.518), 廣州音字典 (p.414), 粵語拼音字表 (p.34), 廣州話方言詞典 (p.190), 廣州話普通話詞典 (p.319), 香港粵語詞典 (p.276), 自學廣州話 (p.106), the Education Bureau site, and 3 sources (Wong, Zhou, Ho) from the CUHK site.
I do find variant readings from two sources. Unicode.org has ‘cing1’ as a variant; but it is not ‘ping4’. The only variant reading as ‘ping4’ comes from Professor Li. According to his suggestion (as seen from the CUHK site), 秤 should be read as ‘ping4’ in the context of 天秤.
I guess ‘cing3’ has all along been the single correct reading for 秤. No one would mispronounce it for such common terms as 呃秤, 抽秤, 唔夠秤, 秤不離砣, etc. But when it comes to 天秤 which meaning is not that clear, people cannot associate this 秤 with the meaning of “steelyard” and “scales”, hence the mispronunciation of ‘ping4’. And this mispronunciation is so widespread that Professor Li has accepted ‘ping4’ as variant reading for 天秤.
I would like to hear members’ comments before we should decide to reinstate ‘ping4’ as variant reading.
