Hi my question is:

"He died of cancer" is all right. What about "He died from cancer." To me , 'die of' is used for internal sicknesses while we use 'die from' for external causes? It is like He died from the air pollution.


Personally, I don't differentiate. Either seems acceptable usage to me.
Yes. He died of gunshot wounds is certainly an external cause.

M-W's Dictionary of English Usage comments:

"From as far back as 1881, there have been varying pronouncements as to which prepositions may be used with which objects after the verb die. Sometimes disapproval is expressed of one preposition or another; Vizetelly 1906 and Copperud 1964, 1970., 1980 do not like from, and Ayres 1881 and Jensen 1935 do not like with. Since as many specifically approve these two prepositions as object to them, there cannot be much of a question of propriety here. But there is still the question of idiom. Here we have some sample texts in which prepositions are used with die in various senses. Of seems to be the most commonly used:

dying of kidney disease
died of too much love
die of horror
dying of inanition
died of starvation

died from an infection
died from lack of enthusiasm
died from too much doubt

died for lack of support

died with pneumonia
died with the cholera

died through neglect."
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Can't we say like this " he died because of canser". To me it seems well too.
Not so much, Yunus. He died of cancer or he died from cancer.

If you want to use because, it would be more in a context like He died because they couldn't get to the hospital on time or He died because he took careless chances or even He died because the gunshot wound caused too much internal damage - but not a strict "cause of death" (like cancer, heart attack, etc.) after because.
I usually say that someone dies of something and that someone suffers from something. I don't know whether in AmE it is acceptable or not, but I've always been told that "to die from something" is not correct. Perhaps we should ask Nona or Mr. P. for further explanations. I would never use "to die because of something", though.

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what about suffer of?

and i saw something about die from as it happens. it seems that die from is more common than die of.

the last thing my question is that is it acceptable to say suffer of?
Ms Google says:

55,200,000 English pages for "suffer from "
1,830,000 English pages for " with"
143,000 English pages for " of