What is the other pronunciation and how to group words

What is the other pronunciation and how to group words


Let's talk
The end of the crossbow
It's difficult for people to reason



How do the two pronunciations of words form words


When reading three tones: language disease, intonation, grammar, vocabulary, sentence, quotation, language, Chinese and mood
When reading four tones, it belongs to written language, when "tell", such as "not to speak"



Bo Bao, how do you make up this pronunciation?


Pancakes, crisp