Mistranslations in the Chinese, Japanese, and Vietnamese versions
When Voldemort moves into his father's abandoned home, the Riddle House, he is a loathesome-looking creature, resembling a crouched human child with hairless, scaly-looking skin that is a dark, raw, reddish-black in colour, thin, feeble arms and legs, and a flat snake-like face with gleaming red eyes.
Care of this gruesome creature falls to the hapless Wormtail, who visibly recoils from looking at or touching his master. We are told that Wormtail stays with Voldemort out of cowardice (he has nowhere else to go) and fear of Voldemort's wrath. It is a testimony to Voldemort's terrible power that even in this pitiful, debilitated state he is able to exercise such control over Wormtail.
Besides Voldemort and Wormtail, there is a third member of this strange little party: a twelve-foot snake called Nagini. For Wormtail, it is understandably quite trying being holed up with Voldemort and Nagini. Even more vexing is the fact that he not only has to feed Voldemort but must also give Nagini milk every night! We learn this from the following exchange between Voldemort and Wormtail in the Mainland Chinese translation:
"Nàjíní zài nǎr?" nàge bīnglěng de shēngyīn
English (meaning translated literally):
"Where is Nagini?" that ice-cold voice sounded.
This passage suggests that Nagini is something like Voldemort's pet cat, who likes nothing more than to lap up a saucer of milk (cow's milk -- 牛奶 niúnǎi) before she retires for the night!
Somewhat later, we learn that Voldemort suspects Wormtail of wanting to desert him. This is a source of great indignation on Voldemort's part. Not only is Voldemort's personal survival threatened, but there would be no one to feed Nagini!
"Rúguǒ nǐ yǒu bié de dìfang kě qù, nǐ jué bú huì dào zhè-lǐ lái de. Ér wǒ ne, wǒ měi ge jǐ xiǎoshí xūyào nǐ wèi wǒ, líkāi nǐ wǒ zěnme huó de xiàqu? Shéi gěi Nàjíni wèi nǎi ne?"
English (meaning translated literally):
"If you had somewhere else to go, you definitely wouldn't come here. And what about me? I need you to feed me every few hours, without you how would I survive? Who would feed Nagini milk?"
This solicitous concern for Nagini's feeding arrangments reveals a kinder, gentler Voldemort than the one we have hitherto known. The touching domestic scene of Wormtail tending to a cranky Voldemort and his cuddly pet snake makes us want to ask why Wormtail would ever want to leave?
We should also want to ask how the Mainland translation has veered so far from reality. The answer, of course, lies in a faulty translation.
The original English version of the above passages is:
"Where is Nagini?" said the cold voice.
"I - I don't know, my Lord," said the first voice nervously. "She set out to explore the house, I think..."
"You will milk her before we retire, Wormtail," said the second voice. "I will need feeding in the night. The journey has tired me greatly."
And later, Voldemort says:
"You would not be here if you had anywhere else to go. How am I to survive without you, when I need feeding every few hours? Who is to milk Nagini?"
Far from having to give Nagini a meal of milk, Wormtail's task is to milk Nagini. Not only that, Nagini's 'milk' has to be fed to Voldemort.
The problem with the translation lies in that simple word 'milk'. Let us take a closer look at the meaning of 'to milk', from Webster's Ninth Collegiate Dictionary (in modified form):
Milk: (verb transitive)
Judging from these definitions, the most appropriate meaning appears to be 2 (a), 'to induce a snake to eject venom'. In other words, Wormtail actually has to milk venom from Nagini's fangs and feed it from a bottle to the repulsive Voldemort in order to keep him alive.
It's not actually clear how Wormtail had to milk Nagini. In real life, a snake's fangs are inserted into the mouth of a jar with a membrane drawn across the top in order to milk its venom. To see how snakes are milked, check out Snake venom, Venoms and Antivenoms, and India Snake Hunters Find Antidote to Joblessness. Perhaps Nagini was a little more cooperative than snakes in the wild, being Voldemort's pet. As to the content of Voldemort's life-giving diet, these sites also give some interesting information on the composition of snake venoms.
At any rate, the Chinese translator, possibly under the pressure of a publishing deadline, misinterpreted 'to milk Nagini' as meaning 'to give Nagini milk'. This changed the nature of Wormtail's relationship with Nagini completely. Instead of having to go through the process of extracting venom from Nagini's fangs, Wormtail simply had to lay out a saucer for her to drink!
Before we finish with this exercise, let's have a look at how the other translators have handled 'milking Nagini'. We'll look at how they have translated the two key sentences above:
"Before retiring, you have to squeeze her juice (or venom) for her again, Wormtail. In the night I also need to eat something again, this trip has tired me out greatly."
There are two points to note about this translation:
First, the substance that is obtained from Nagini is called 汁 zhī. Literally this means 'juice' or 'extract'. It can, however, also refer to snake venom, occurring in the expression 毒汁 dúzhī (poison juice = snake venom). I am not sure whether it would be immediately understood that way by a Chinese speaker, though.
Second, the translation says 替娜吉妮擠汁 tì Nàjínī jǐ zhī ('squeeze milk on Nagini's behalf'). The auxiliary verb 替 tì means to do something on behalf of someone else, or simply to help someone do something. In this case, it implies that Nagini actively wanted to give her 'juice' or 'venom' but was unable to squeeze it herself so Wormtail had to do it for her. If so, the traditional way of milking a snake (shown in the links above) may not fully apply as Nagini was presumably docile and cooperative.
In this translation, Wormtail has to エキスを絞る ekisu o shiboru, literally 'squeeze (Nagini's) extract', i.e., to squeeze the extract out of Nagini. The word エキス ekisu is from English, being an abbreviation of the word 'extract'. The meaning of エキス ekisu is 'extract' or 'essence', so Wormtail has the job of squeezing 'extract of snake' or 'essence of snake'.
It is not actually clear what 'essence of snake' might be. In this case, the translator has either mistaken the meaning of 'to milk' (i.e., to extract venom) and decided that an extract or essence is meant, or she has decided that having Voldemort drink venom from a snake's fangs would be altogether too revolting and has changed the meaning deliberately.
The Vietnamese translator uses vắt sữa 'squeeze milk', which means 'to milk'. Nagini actually produces milk according to this translation. While sữa is applied to substances other than 'milk' -- sữa cây 'tree milk' is 'tree sap' or 'latex' and sữa dừa 'coconut milk' means exactly that -- to the best of my knowledge, sữa is not used for snake venom.
To sum up, the four translations are as follows:
Take your pick!