When do I have to pronounce the pronoun 谁 shui and when shei?

Both are ok but shui is more standard and shei is a local variation, mostly used in the north/Beijing areas. If you study in Beijing they will surely teach you shei. It is said that shei is a "lazy" form of shui. I much prefer shei as well since it is so much easier to get correct compared to shui.

In reality pretty much everyone uses shei on the mainland. I think I've heard it pronounced shui only once on some TV program.

Just baidu'd and found a douban discussion - apparently it's the same in Taiwan. Some excerpts:

我听到电视里的播音员说 shui2 也是很别扭。在台湾，我们的标准发音是 shei1，没有人读作 shui2。
"When I hear people on the TV say shui it sounds awkward. In Taiwan, our standard pronunciation is shei, no-one says shui"

Another person says
照《现代汉语词典》shui是shei的“又音”
According to the Modern Hanyu Dictionary, shui is an alternate pronunciation of shei.

Another person says "people in the south use shui", someone responds:
南方人多用shui？？？？？？？？？？
为什么我周围的全部念shei？？？？？？？？
Southerns use shui????????
Why is it everyone around me says shei?????????

I think that's fairly conclusive....

shei = who is it? (somebody is at the door.)
Shei? (used as a single word.)


shei = wo made it?
Shei gande? (used in the BEGINNING or MIDDLE of a sentence.)


shui
Ta shi shui? (used in the END of a sentence.)

learninglife, only in the realm of textbooks!

And my parents in law:-) Old generation and never using shei. Also, depending on what dictionary you use the spelling is different, take 反切 e.g. who claims shui to be correct. So does 漢語大詞典 However, absolutely agree that most common today is shei. My teacher back in Beijing also refused to use shei and er, partly because of her age and partly since she where from inland China i guess.

Point accepted! I rarely talk to old people...

Not too long ago, shuí was the native reading. It was called 文读 (literary reading) and was used when reading aloud and in formal setting.
shéi was an altered reading influenced by the Mongolians and Manchurians during the Yuan 元 and Qing 清 dynasty. It was called 白读 (colloquial reading) and was used in less formal occasions.

Since the people in south are less influenced by these foreigners, they retain the shuí reading for all occasions.

Then the 《 普通话异读词审音表》 is issued and declared that "谁 shéi ，又音shuí 。"
That changed everything, and now shéi is the standard reading and shuí is only an alternate pronunciation .

twasnt copied from textbook, byzanti :)
it was real life experience here in beijing.

lorenzo,
saying thank you would be nice if people care to answer your question.
dont forget it in the future!

@learninglife if you expect everyone to thank you for every comment you make on the Internet, you have a life of bitter disappointment ahead.

:) still expecting the best

Please do not thank people after every question. It will only clutter up the forums.

@icecream: Thank you for pointing that out :)

I disagree with icecream, I think saying thank you is a nice thing to do, particularly when someone has gone to some effort (as pts often does, for example) to research an answer.

James

Oh, gosh! You're perfectly right; I'm so sorry I offended you! I haven't got internet for two or three days since I'm on holyday and here internet points cost a lot!
I thank you for answering and apologize to you.