I'm a (non-native, formerly fluent but now pretty poor) Cantonese speaker and I'd describe the difference between Cantonese and Mandarin as roughly the difference between Portuguese and Romanian. Sure, they're both romance languages, and maybe with a lot of work and hand-waving and drawing characters on your hands with your fingers you can get your point across to someone who speaks the other language, but in no way would I call them mutually intelligible, even by talking "slower".
Cantonese and Mandarin have very different pronunciation, vocabulary, and even grammar for common cases. In fact there are extremely common words in Cantonese for which there is no modern chinese character: instead roman words or even single letters (like "D") are substituted in comic strips etc. So you can't even write them down in Chinese for a Mandarin speaker to puzzle through with a dictionary.
I'd say that your perception of these things as "western centric" -- they are not at all -- strikes me as very "northern Chinese centric" view of China. :-)
See e.g. this video: https://www.youtube.com/watch?v=Ps7_NnkL-oM where for almost the entire video a couple is explaining words in their respective dialects (Sichuanese and Hunanese) to one another in their own dialect (i.e. not using Standard Mandarin at all in their explanations). The first half of the entire exchange is fluent and understandable by both people and also a Standard Mandarin audience. Only in the second half when they intentionally start quizzing each other on words they know will be tough for the other person and without additional context do they run into trouble (and occasionally resort to Mandarin).
Also, comparing it to Romance languages masks some complexities of the relationship. https://news.ycombinator.com/item?id=16844074
Have you ever watched either Ip Man or "The Bridge" (Danish/Swedish cop show)?
In Ip Man, there's a gang of Mandarin speakers who show up in Ip Man's Cantonese world. They somehow are able to speak to each other, and I find it unlikely. Perhaps it's because my Cantonese is mediocre. But it just doesn't sound like you could have a casual conversation across the languages.
A similar thing happens in The Bridge. There's two cops solving a crime on the bridge connecting Denmark with Sweden, and they just talk to each other in their own languages. My guess is most people who didn't study the other language would not know all the slang, as importantly the simple expressions. Though I guess it could be learned easily; I can read a Swedish newspaper, just not process it fast enough to have a fast conversation with a colleague.
Similarly with German and Swiss German. Something about the way the sounds are different makes processing the other one a bit slow if you're not used to it.
So the mixed Mandarin / Cantonese conversations actually do happen. My wife's family are all native Cantonese speakers, but her uncle married into the family from another part of China. He understands Cantonese perfectly but is more comfortable speaking Mandarin; and everyone else understands Mandarin to various degrees but prefer to speak in Cantonese. So he just speaks Mandarin while everyone else sticks to Cantonese; and it's quite a fluid back-and-forth.
That said, for that to happen so naturally the way it does in the Ip Man movies is really unrealistic. First of all, Mandarin wasn't as well-known in Guangdong in the 1930's as it is now; and there's no way someone from another part of China could just show up and magically understand Cantonese: It would take at least a few months of immersion to be able to "listen" fluidly enough to have that sort of a mixed conversation.
Even more unrealistic is Ip Man 4, where he shows up in San Fransisco, and starts talking in Cantonese to people who have immigrated from Beijing -- including one of the character's 12-year-old daughter who grew up in San Fransisco. Yeah, that's not going to happen.
[Minor grammar edits.]
It's probably the case that all the often used words that you use in everyday life have changed, but once you get over the barrier there's a pretty smooth learning zone.
But there are a huge number of words which are simply pronounced a bit differently; and the differences in pronunciation have a lot of predictable patterns. So once you're familiar with these patterns, suddenly a Mandarin speaker can understand a huge amount of Cantonese when spoken in context.
This is definitely not true (if they were to use their own dialect).
I'm from the same region surrounding Shanghai and although there are some intelligibility between dialects, it is hard if not completely impossible to have a conversation even between people from adjacent towns. See https://en.wikipedia.org/wiki/Wu_Chinese
I'm a bit surprised about your claim. Anyone from China with a sense of the dialects of the south would know this.
the problem is that spoken cantonese is not much like written cantonese. it's a combination of pronunciation, accent, idioms, and sentence structures. best advice is for speakers of mandarin or cantonese to learn the other language like a new one. (there's also the written form of spoken cantonese, written spoken cantonese, if you will, that is the written representation of spoken cantonese using a set of special characters of sinitic origin).
if you are from guangdong you will learn all systems of language - written mandarin, spoken mandarin, written cantonese, and spoken cantonese. some hongkongers don't ever learn spoken mandarin correctly, getting them to speak mandarin in front of a camera is always a source of good laughs.
those who argue that cantonese are mutually intelligible with mandarin will typically use cantonese newspapers and official documents as evidence. those who argue that they aren't will point to spoken and colloquial cantonese as evidence. the objective point of view is to accept that cantonese as we know it exists as two separate languages used for two different purposes.
1. https://audio.tatoeba.org/sentences/wuu/488406.mp3
2. https://audio.tatoeba.org/sentences/wuu/485590.mp3
3. https://audio.tatoeba.org/sentences/wuu/485698.mp3
4. https://audio.tatoeba.org/sentences/wuu/488621.mp3
5. https://audio.tatoeba.org/sentences/wuu/489046.mp3
6. https://audio.tatoeba.org/sentences/wuu/489736.mp3
7. https://audio.tatoeba.org/sentences/wuu/492871.mp3
8. https://audio.tatoeba.org/sentences/wuu/496402.mp3
9. https://audio.tatoeba.org/sentences/wuu/485676.mp3
10. https://audio.tatoeba.org/sentences/wuu/488252.mp3
They're not especially slow, but you can replay them as often as you want or even slow them down, so I think it should be easier than for someone in Chengdu trying to understand a Shanghainese speaker in person.
For comparison, here are the Mandarin equivalents of those sentences, pronounced by the same speaker:
1. https://audio.tatoeba.org/sentences/cmn/332870.mp3
2. https://audio.tatoeba.org/sentences/cmn/332436.mp3
3. https://audio.tatoeba.org/sentences/cmn/332568.mp3
4. https://audio.tatoeba.org/sentences/cmn/333012.mp3
5. https://audio.tatoeba.org/sentences/cmn/333070.mp3
6. https://audio.tatoeba.org/sentences/cmn/333151.mp3
7. https://audio.tatoeba.org/sentences/cmn/333392.mp3
8. https://audio.tatoeba.org/sentences/cmn/333584.mp3
9. https://audio.tatoeba.org/sentences/cmn/332549.mp3
10. https://audio.tatoeba.org/sentences/cmn/332788.mp3
And here they're written down, together with translations into various other languages:
1. https://tatoeba.org/cmn/sentences/show/488406
2. https://tatoeba.org/cmn/sentences/show/485590
3. https://tatoeba.org/cmn/sentences/show/485698
4. https://tatoeba.org/cmn/sentences/show/488621
5. https://tatoeba.org/cmn/sentences/show/489046
6. https://tatoeba.org/cmn/sentences/show/489736
7. https://tatoeba.org/cmn/sentences/show/492871
8. https://tatoeba.org/cmn/sentences/show/496402
9. https://tatoeba.org/cmn/sentences/show/485676
10. https://tatoeba.org/cmn/sentences/show/488252
If you want some more examples, this search returns a few hundred: https://tatoeba.org/cmn/sentences/search?query=&from=wuu&to=...
Regardless I certainly would not view Shanghainese as mutually intelligible with Mandarin.
If you check the logs on the sentence page, you'll see that the Shanghainese sentences are actually translated from the Mandarin. So she was going from relatively formal Mandarin to more informal Shanghainese, probably because that's what she's accustomed to speaking.
I didn't really intend these as a demonstration of how different Shanghainese and Mandarin are even when you translate as literally as possible, but more as a way for people on HN who know Mandarin but haven't had much exposure to Shanghainese to try and see how much they understand. I like to think I understood a few words like 自己 and 警察, but maybe that's because I looked at the text first.
I think you've also answered my questions in this space before, what kind of work do you do? You seem very familiar with asian languages deeper than just a native speaker/hobbyist might be.
I thought recording 6 was vaguely mandarin sounding, if you squinted you could more or less guess what was being said. Agreed that the rest are hard to understand but I don't think it takes native mandarin speakers much effort to get to a point where they can get proficient in another dialect. IMO learning Shanghainese from Mandarin will be easier than learning Portuguese if you speak Spanish