Nasal does have something to do with climate. I (Hong Kong) and you (Malaysia) are from the tropical region. And most English speakers and Tom are from places where it snows. When the weather is real cold, people don't breathe too deep and produce nasal voice. I guess that is why even foreign accents can be classified into regions.
One of my friends speaks Cantonese with nasal quality after moving to Canada for five years.
That really makes sense to me!
I've never thought of it maybe that's no season changing in my country.
Thanks for your point!
I got a rather controversial point here... Does it mean they will sound "nasalized" during winter? What about other seasons...?
What if an European who has been staying in tropical region for a long period (let say 10-20 years), will he lose his "nasality"..?
Hope to hear from you again.
I think it is easier to change from non-nasal to nasal than the other way around.
I see some really examples in the first condition but many priests, one Cantonese speaking British actor in Hong Kong still speak with some nasal quality.
It is not about season. It is about which latitude we are located on. Go to Korea or Northern Japan in winter to get to know what is about speaking without opening the mouth too big or else the freezing air will cut your throat.