Particularly in the Philippines, the reason why a person from one region pronounces the same word differently from someone from another part of the country may then come as a surprise to you.
Did you know that the original Philippine alphabet, most likely the foundation of all our contemporary dialects, called 'Baybayin' or more commonly known as 'Alibata', only had three vowels? Yes, just three.
They are "A", "E or I" and "O or U". E or I? O or U? Yes, the use of "E" and "I" are interchangeable, and so is the use of "O" and "U"
This accounts for why both "Lalake" and "Lalaki" are acceptable pronunciations of the same word. And so with: Kain and Kaen, Multo and Molto, Diyos and Deyos, Laki and Lake.
So, the next time you hear a person from a different region as yours pronounce the word "kuya" as "koya", or vise versa, think hard about who is correct. In this case, both of you are.