这不可能 - 用户只能在设置中更改他们的语言。

No this is not possible - user can only change their language in the settings.

但是，如果你可以给用户一个英语键盘选择（或询问他们的偏好）

However you can give the user an "English" keyboard if you choose (or ask them their preference)

你这样做是使用： UIKeyboardTypeASCIICapable

您可以通过按下底行的地球图标直接在键盘上更改键盘。

You can change keyboard directly on the keyboard by pressing "globe icon" on the bottom row.

首先，您必须在设置中为这些语言启用这些语言。然后按键盘上的地球按钮将在这些语言之间切换。

First, you have to enable those language for input in Settings. Then pressing the globe button on the keyboard would toggle between those languages.