I don't speak Chinese or Japanese, but people that do told me that there are more than five ways to pronounce "yi", they all mean different things, but they're all transliterated to English in the same way.
That's because Chinese is tonal. There are 5 different tones in Standard Mandarin. When transliterating Chinese to the English alphabet, there is no way to write the tone, so you introduce ambiguity that wasn't officially present.
That's because Chinese is tonal. There are 5 different tones in Standard Mandarin. When transliterating Chinese to the English alphabet, there is no way to write the tone, so you introduce ambiguity that wasn't officially present.