Since it is showing Pinyin above the word “machines” that makes me think you’re reading the text in the Chinese section and not the English section. But in that case I think it would not be possible to get any definitions, if your languages are set to “I know Chinese” and “I’m learning English.” Do you see something like this at the top? When I switch my language to 中文/English like this and read an English text, I do not see any Pinyin when I click words, only characters.