Yeah that stuff still confuses me. I have heard that when you have 2 characters with the 4th tone, the first character changes to the second tone. For example, 不(bù) and 是（shì) are both 4th tone but together they become bú shì but I have seen other characters that don't follow this rule like 望而却步(wàng ér què bù) or 后缀(hòu zhuì). Can you give me some clarification on this?
Cantonese looks and sounds like a nightmare. I have been slowly learning it from time to time just for fun.
Sadly I'm definitely not the right person to ask about learning Chinese as I'm still learning myself. But what I was told with 不 and 一 is that if they follow a 4th tone word they are pronounced 2nd tone, and if they folow a 1st, 2nd or 3rd tone word, it is pronounced 4th tone.
Cantonese and English is my thing, Mandarin I get by winging it !!!
Do you know any good resources for learning Cantonese? I am located in northern China which means hardly anybody (if at all) speaks Cantonese here.