I started to learn Cantonese 粤语 recently from Duolingo. While I forgot many 宁波话 Ningbo dialect since I went to college in Wuhan: I started to speak much more mandarin since then. I was wondering about the similarities between two dialects (Cantonese and Ningbo Dialect) 粤语和宁波话是否有共同之处 (google search).
A related question I had earlier is whether 粤语更接近古汉语吗 (again google search). 粤语是保留了最完整的古汉语 (360doc). Quote
在全球使用粤语人数甚多，广东使用粤语的人口大约有6700万，加上广西粤语使用人数大约为2500万、香港700万、澳门55万、泰国500万、新加坡和马来西亚500万、美国和加拿大200万，全球将近有1.2亿人口使用粤语。
YT – in English – Why Cantonese is Closer to Ancient Chinese than Mandarin
救救方言，救救城市的灵魂 – 原创 土哥涅夫 秦朔朋友圈 – 来源：澎湃新闻·澎湃号·湃客 – quote below and this seems matched my rough observations too
都说入乡随俗，过去人们移居一座新的城市，往往会通过学习当地方言来融入本地社会。但如今，随着大量外地人口涌入长三角，反而冲淡了本地的语言环境，甚至于出现了“上海内环内说英语，中环内说普通话，外环外才说上海话”的奇怪现象。
记得前几年，网络上曾流传过一张《6-20岁能够熟练使用方言人群比例》的图，其中吴语的使用比例全国垫底，像杭州话、温州话、宁波话，本地青年人能熟练使用的比例均已低于10%，苏州话更是只有2.2%，濒临消亡。这自然激发出吴语区人民的母语危机感。
今年初《繁花》电视剧为什么会大火，引发如此多的关注和讨论？未必是这部剧本身有多好，在我看来，相比当年的《股疯》《孽债》，香港人王家卫拍的是他心目中想象的上海，这个“上海”里人物穿着打扮、品味审美的精致程度，更接近民国，而非90年代的上海。
PS: when I was in college, the Cantonese pop songs or #Cantopop were very popular in colleges and in the China. Here is a playlist on YT – 經典粵語歌曲 – 香港90年代流行經典廣東歌回顧 | 必听经典粤语歌 – Cantonese Golden Songs: 張學友，陳慧嫻，叶丽仪, 张国荣, 谭咏麟, 陈慧娴, 陈百强, 梅艳芳。In fact, one of my roommates would sing this one almost everyday – 一生何求 (the 1st song in the playlist above, here is a standalone YT video – 陳百強 Danny Chan -《一生何求》Official MV (電視劇《義不容情》主題曲). I didn’t think too much about learning Cantonese dialect then. Although in Spring 1993, a few roommates went to Guang’zhou (and Guangdong province) looking for jobs. Note at that time Guangdong province was much more economically developed than my college town Wuhan, as it was close to Hongkong, and it was the very 1st province opened to the outside world in 1980s. Quite a few of my classmates in college went there to work after graduation.
Last but not least, 中国10大最难懂方言：排名第一的，并非粤语、闽南语. Again quote a bit below:
有句俗话说宁听苏州人吵架，不听宁波人说话，充分说明了苏州话的“软糯”。
因为温州话是第一名，这里有一个油管视频：连温州人都听不懂的温州话 (吳儂軟語 Wu Chinese)