There was also
- Bird calls/Bird tweets
- Dialogue between rocks
I speak both Mandarin and Cantonese and here are some of my observations/speculations:
Both Evelyn (Michelle Yeoh) and Waymond (Ke Huy Quan) use both Mandarin and Cantonese (though mainly Mandarin and only a little Cantonese). Both speak Mandarin with "non-standard" (non-Northern/Beijing) accents.
Evelyn's Cantonese is more close to "standard Hong Kong"; Waymond's much less so.
Gong Gong speaks only Cantonese (though Alpha Gong Gong also speaks English).
Joy speaks Mandarin and not Cantonese. She speaks Mandarin with a distinctly "standard" accent--so one possibility is that she learnt Mandarin in school in the US and didn't pick up either of her parents' Mandarin accents.
I'm pretty sure the flashback/multiverse scenes are to Hong Kong based on these clues: (1) When Evelyn is born, the doctor speaks to Gong Gong in Cantonese; (2) There was a shot with a Hong Kong taxi; (3) Some shots had traditional (rather than simplified) Chinese characters; (4) The movie-within-movie credits were in the style of 1970s-90s Hong Kong cinema.
That Evelyn and Waymond speak both Mandarin and Cantonese to each other (and in non-standard accents) suggests they do not share the same strongest (or "native") language.
So, one possibility is that Waymond is not a native Cantonese speaker; was from some other part of China or the world, moved to Hong Kong, where he learnt Cantonese and also met Evelyn.
A few more notes:
Mandarin and Cantonese are completely distinct languages (as different as English from say German).
Michelle Yeoh grew up speaking English and Cantonese (source: Financial Times interview, 2023). She only learnt Mandarin when preparing to film Crouching Tiger, Hidden Dragon (source).
Ke Huy Quan is Chinese-Vietnamese, but I'm not sure when/how he learnt Mandarin and Cantonese and whether he would consider one of these two his stronger or "more native" language.