I come from Jiangsu. I am a college student in the north, and I have no Cantonese environment at all, so I have no chance to speak, but I don't think it's a big problem. I went to Guangzhou as a social worker for a month after graduation. I once called the lonely old people and empty nesters in the community one by one and prepared to visit them one by one. The old people are very happy and excited to know that we are social workers and want to visit them.
At first, I used Mandarin. Later, an old man might not be used to it. When he asked me to speak Cantonese, I said that the communication was smooth and I used Cantonese for the next calls. Several Guangdong colleagues next to me couldn't help applauding me after seeing it. It was the first time I used Cantonese, and then I watched many original Hong Kong movies and expanded some slang and common sayings.
On one occasion, we organized community activities for the elderly and held a lecture on TCM health knowledge. I teach in Cantonese. Considering that I may not be able to express some words, I am lucky to have my beautiful colleague from Maoming, Guangdong, but it turns out that my lecture was not very successful. At that time, there was nothing wrong with my daily communication in Cantonese, but when it came to knowledge of Chinese medicine, it was not very smooth.
At that time, I was too young and immature to think of this problem. If I were now, I wouldn't dare to speak. There is nothing wrong with the language, mainly because my understanding of Chinese medicine is still very shallow and it is easy to mislead others.
At first, I downloaded a book "Cantonese Phonetic Alphabet, Grammar, Special Vocabulary" on the website and printed it out. After only a few days of study, I basically mastered it. Most words in Cantonese are the same as those in Mandarin. Then I downloaded some Cantonese radio dramas, put them on mp3, and listened to them before going to bed at night. I didn't understand it very well at first, but after listening for about ten days, I can basically understand 70 ~ 80%.
I still remember the titles of several radio dramas, such as Love from the Beginning by Deng Jianhong and Zheng Rong (the first Cantonese radio drama I heard at that time), and Sleepless at Night by Hins Cheung and Huang Yiwen (a radio drama that made me break through the critical point of understanding Cantonese).
I was very excited at that time, and then I went to watch Hong Kong dramas, and even stayed in Internet cafes for two or three nights and watched some TVB dramas. Later, when mp4 came out, I bought one, downloaded the drama online and loaded it into mp4, and took it back to the dormitory to watch it slowly, so I didn't have to stay up late. Add it up before and after, it will take about a month, and I have basically learned it.
A few years later, I went to the temple and lived there for half a year. I know a lot of Cantonese people, and sometimes it is very comfortable to communicate with them in Cantonese and even Buddhism. Now, you should be more fluent than then. You don't need subtitles to watch Wong Tze Wah's Dong Duixiao.
The above is my experience in teaching Cantonese by myself.