Should I pronounce “er” as [ɚ] or [aɚ̯]?

Question

What I learned growing up was that words with the pinyin “er”, like 儿, 二, and 耳 were pronounced [ɚ], but younger/more native speakers of Standard Chinese seem to pronounce it as [aɚ], and I was wondering if I should switch my pronunciation over to that.

Wikipedia’s page on erhua has some nice information on these “non-erhua r-colored syllables” but is still a bit vague about exactly which type of people are using which pronunciations:

All of the non-erhua r-colored syllables have no initial consonant, and are traditionally pronounced [ɚ] in Beijing dialect and in conservative/old Standard Mandarin varieties. In the recent decades, the vowel in the toned syllable "er" has been lowered in many accents, making the syllable come to approach or acquire a quality like "ar" (i.e. [aɚ̯] with the appropriate tone). In some new accents and some different accents than Beijing, all the non-erhua r-colored syllables (may) use "ar"-like qualities regardless of tones.

So, what are the different connotations of the two pronunciations? How recently did the shift happen? Does [aɚ] make you sound young and [ɚ] make you sound old? Is one pronunciation more prestigious than the other, and the other more casual? Is there a Northern/Southern divide?

Answer 1

The whole syllable 'er' and the retroflex syllables 'er' (as in 'ler', 'ger' ...) behave differently regard to this question.

For the whole syllable 'er', 'er2'(而), 'er3'(耳) and 'er4'(二) are in fact different. 'er4' is pronounced as 'ar4'. See this article. As when the difference came I do not know. I only begin to notice this when I started doing research in TTS (Text-to-Speech).

For retroflex syllables, I haven't noticed similar phenomena. Every syllable seems to be pronounced the same.

But as said in the wikipedia article, the mentioned shift happens in certain dialects/accents. I am not familiar the variation of sound in dialects.

I do not think the pronunciation difference can make one sounds younger or older, or more formal or mare casual.

Answer 2

The IPA article for Mandarin on wikipedia has a clear example:

IPA | Pinyin | Wade–Giles | Bopomofo | Chinese Example | English approximation

ɚ | er | êrh | ㄦ | 二 | sir (American English)

There are no instances of [aɚ] on the Wiki page, either. The [aɚ] mentioned on the page you are referring to is for 儿化 (erization) and not individual syllables like 儿, 二, and 耳.

Answer 3

I am not an expert, so I cannot explain as a professional would, but in my observation:

1. er (而, 耳) and erhua are different.

2. 二 is a special one, it falls in the category of er, but its pronunciation is [aɚ]. In some areas, people say [ɚ], in 普通话, it should be [aɚ].

3. erhua, for me, is just a lazy way to speak. You drop the last phoneme, substitute it with an easy one [ɚ].

For example, 一会 (yi hui), drop the last 'i' in 'hui', then it becomes 'yi hu' which sounds strange, so you curl your tongue naturally to make a sound similar to '[ɚ]' , 'yi huir'.

Erhua is originally used by Manchu in Beijing in Qing dynasty, their speech sounds lazy. They tend to omit the last phoneme, then form a new way to talk.