The Last Emperor is mostly in English, but it is meant to be understood that this is simply being translated for the benefit of the movie viewer, usually from Mandarin (I think).
Was Reginald Fleming Johnston (the Emperor's tutor) supposed to be speaking in Mandarin most of the time (when he was communicating with the Emperor and other folks in the Forbidden Palace)?
From the original script, it's not immediately clear. On the one hand, Johnston ("R.J.") is clearly fluent in Mandarin:
RJ stares at the faces which begin to peer in through the car windows. A grinning TWELVE YEAR-OLD slaps a poster against the glass.
R.J.(points at the ideogram on the poster) "China awake..."
and at the same time, the Emperor shows a strong understanding of written and spoken English:
Pu Yi points at a portrait on the cover of the Post — a special "Independence Day" issue.
PU YI: Who is this "George Washington"?
Since they can both communicate in each other's languages (and since the Emperor is eager to learn about the outside world) I'd imagine that they would speak English whenever possible.
Elsewhere in the Forbidden City, Mandarin would obviously be the lingua franca for general conversation.
In real life (according to From Emperor to Citizen: The Autobiography of Aisin-Gioro Pu Yi) Johnson spoke fluent Mandarin, although he made no attempt to speak with a Chinese accent, much to the young Emperor's amusement.
I found that Johnston was not so frightening after all. His Chinese was very fluent and much easier to understand than Chen Pao-shen’s Fukienese or Chu Yi-fan’s Kiangsi dialect. He must have been at least forty at the time and was clearly older than my father, but his movements were still deft and skilful. His back was so straight that I wondered whether he wore an iron frame under his clothes. Although he had no handlebar moustache or “civilization stick” and his legs did bend, he always gave me an impression of stiffness. It was his blue eyes and greying fair hair in particular that made me feel uneasy.
During one lesson about a month after he first came he suddenly turned round and glared furiously at the eunuch who was standing by the wall. His face red with anger, he protested to me in Chinese spoken with an English accent:
“The Household Department is treating me very discourteously. Why do I alone have to have a eunuch standing here when the other tutors don’t? I don’t like it. I don’t like it and I’m going to bring the matter up with President Hsu as it was he who invited me to take this post.”
They spoke a mixture of English and Mandarin Chinese when they were in their lessons.
As I gradually realized how diligently Johnston was teaching me I was very pleased and willing to be more obedient. He did not only teach me English; or rather teaching me the English language was not so important in his eyes as training me to be like the English gentlemen he talked about. When I was fourteen I decided to dress like he did and sent some eunuchs out to buy me a large amount of Western clothing.
Johnston would persistently use English words when they were speaking in Chinese, ever the teacher.
I was called Henry and my empress Elizabeth. I even imitated his way of talking in a mixture of Chinese and English when I was with my fellow-students:
“William (Pu Chieh), sharpen this pencil (I used the English word) for me ... good, put it on the desk”
“Arthur (Pu Chia), tell Lily (my third sister) and the others to come round this afternoon to hear some foreign military music.”
When I was a child, my parents had bought this film on VHS in French. I can't quite recall what they were speaking throughout the movie, I'm currently watching it in English and it's so weird, it feels like they ought to be talking Chinese, and not just because they are Chinese (I should dig it up, but I think they were talking Mandarin with French subtitles). I do remember the character Reginald Johnson speaking English most of the time. So no, I think he was indeed supposed to be talking English. He was his tutor after all, so it would only make sense.
