I asked around and tried to find out why the letter "G" is pronounced like 居 by many people here in Taiwan, but all to no avail. Nobody seems to know why.
I'd think 技 or 機 sounds much closer to G than 居.
Then a smart friend of mine, A, offered a very convincing explanation.
According to A, the shape of the lips when G (dʒiː) is properly pronounced looks very much like the shape of lips when reading 居. Students LOOK at instead of LISTENING to how their teachers pronounce the alphabet G. Hence we hear people say 居 every time when it comes to G.
Sight over Sound..., no wonder it doesn't sound right.