Oh I didn't know the current alphabet came from the Portuguese. I assumed it was from the French when they colonized Vietnam.
The point about the logographic characters being distinct is interesting. I guess if you don't have to phonetically spell it out you have some more freedom in picking what written characters will represent the meanings of the two words. It is still a shame we ended up with those homophones, but I guess that's just a path dependency thing since the spoken words came first. I guess they just had to work with what they had when they converted them into characters.
I guess at the heart of my question is: Why people didn't create new letters to fit those sounds? Sure initially people would have to learn what the new letters are so they could pronounce them, but they already have to learn all these rules and exceptions so they can pronounce the reused letters correctly in the right circumstances. Why can't we have 38-56 letters?