PuTongHua or Guoyu, also called standard Mandarin, is one of the only 2 Chinese varieties standardized. Thus, some may think its pronounciation never changed. However, some sonud changes happened throughout years and were absorbed as new standard. Therfore, the standard pronounciation did change. Here I list some of them, some may be well known and some may be my own observations and is controversial, so correct me if I am wrong.
1. bo po mo fo > buo puo muo fuo
When ppl first learnt the pinyin, some may be confused abt the pinyin of bo po mo fo, at least I was. What I heard was absolutely buo puo muo fuo, but the pinyin was spelled as bo po mo fo. The reason is, when pinyin and standard Mandarin was first established, they did sound like how they are spelled, however, as o is a rounded lip vowel, it affected the consonants before it, forming a glide w between them, thus sounds like buo puo muo fuo, but the spelling remain the same.
2. j q x > z c s
This is an ongoing sound change. Originally, there were no j q x in Mandarin. When z c s are followed by i or ü, they were affected and palatalized to become j q x. On the other hand, g k h also became j q x when followed by i or ü. So j q x in modern standard Mandarin came from 2 sources, gkh and zcs before i or ü, they are in complimentary distribution, which means zcs and gkh will not exist before i and ü while jqx can only exist before i and ü. Thus, they have no function of differentiating meanings. Many cannot distinguish jqx and zcs(which is useless from the viewpoint of differentiating meanings), and pronounce jqx closer to zcs, shifting the pronounciation to what it was.
3. in-ing merger
This is a famous sound merger. The native Chinese dialects do not distinguish in and ing. When these native speakers speak standard Mandarin, they bring this feature into their accents, and even affect other accents.
4. w(/w/) > /ʋ/
Sorry for using IPA. But this is a very noticeable sound change. /ʋ/ is a labiodental approximant, which means you pronounce it by placing the lip and teeth to the position of pronouncing f sound but pronounce it like w sound. It is a free variation of /w/ and will not affect the meaning. This mostly occur in northern accent, but it is becoming a general trend.
“Sorry for using IPA” in a post about phonology 🙄
> bo po mo fo > buo puo muo fuo […] The reason is, when pinyin and standard Mandarin was first established, they did sound like how they are spelled […]
The change from -o to -uo isn’t recent, as you can see in [the difference between Wade-Giles romanisation and Pinyin/Zhuyin](https://en.wikipedia.org/wiki/Wade%E2%80%93Giles#Vowel_o). This was a sound change that was happening throughout the 19th century, and would’ve been completed by the 20th century, probably before Pinyin was promulgated. Pinyin itself was delivered after a very messy process, so it’s anyone’s guess why that change wasn’t incorporated.
>however, as o is a rounded lip vowel, it affected the consonants before it, forming a glide w between them
This is a *post hoc* rationalisation for the sound change. English speakers can pronounce the vowel o just fine without forming the w glide, e.g. bow, poke, mote, fold.
>j q x > z c s This is an ongoing sound change. Originally, there were no j q x in Mandarin. When z c s are followed by i or ü, they were affected and palatalized to become j q x. […] Many cannot distinguish jqx and zcs(which is useless from the viewpoint of differentiating meanings), and pronounce jqx closer to zcs, shifting the pronounciation to what it was.
Since you’re also a Cantonese speaker, I should point out that this is accurate only for some southerners. Your description is accurate enough: j/q/x and z/c/s are allophones, and the former comes from the palatalisation of the latter. That doesn’t mean the vast majority of speakers don’t distinguish them, and the existence of Pinyin itself acts as a source of inertia.
[Palatalisation](https://en.wikipedia.org/wiki/Palatalization_(sound_change)) is a category of sound changes that occur in a variety of settings, so while the palatalisation of z/c/s in front of i/ü may be unnatural for you, it may not be so for many others.
FWIW, de-palatalisation has also occurred in Cantonese:
>[The affricates /t͡s/ and /t͡sʰ/ also have a tendency to be palatalized before the central round vowels /œː/ and /ɵ/. […] One shift that affected Cantonese in the past was the loss of distinction between the alveolar and the alveolo-palatal (sometimes termed as postalveolar) sibilants, which occurred during the late 19th and early 20th centuries.](https://en.wikipedia.org/wiki/Cantonese_phonology#Historical_change)
However, for the reason I’ve cited above, it’s unlikely that this would become a sound change in Mandarin.
>in-ing merger This is a famous sound merger. The native Chinese dialects do not distinguish in and ing.
As others have pointed out, this isn’t true. There are plenty of Chinese dialects that do distinguish between -in and -ing when both occur.
Another one that I think has happened is 天、言、间 etc. sounding more like “ti**e**n” “y**e**n” “ji**e**n” instead of “ti**a**n” “y**a**n” “ji**a**n”. (But this change is not recent).
However, as for the second and third changes that you mentioned, I don’t see the second change happening at all. ji qi xi sounds quite different from zii cii sii, and I find ji qi xi to be easier to pronounce than zii cii sii( I think it is, otherwise why would the pronounciation change from zii to ji).
For the third one I think it is actually the opposite, more and more people can differentiate between “en,eng” and “in,ing”. Some southern dialects also do not have both “zh ch sh” and “z c s” sounds, so if you go to a city like Shanghai you might find some adults who sometimes mistakenly pronounce a “sh” into a “s” or vice versa. However, if you look at the younger generation, there is no such mixing of sounds.
I don’t know where you observed these “trends”, but definitely not in China. The trend in China is totally the opposite; more and more people distinguish in/ing or en/eng.
The old generation in the South is bad at telling the difference between in and ing, but the younger generation clearly distinguishes them, based on my first-hand experience with my college classmates.
Most Chinese people, old and young, can easily distinguish jqx vs zcs. They are vastly different, and I have never noticed any changes. I just can’t imagine anyone pronouncing 积极 as 自己。
cool post !