Why isn't the "i" in rider phonemically different from the "i" in writer?
I pronounce rider as /ˈɹaɪɾɚ/ but writer as /ˈɹɐɪɾɚ/. I also pronounce the "ider" in spider differently from the "ider" in rider and more like how it's pronounced in writer. Wikipedia labels this distinction as allophonic; I know the main argument for the distinction being allophonic is that native speakers are unaware of the difference between these two sounds, however the same can be said about actual phonemes. For example, some english speakers, formerly including myself, do not really acknowledge the difference between /θ/ and /ð/, yet they still pronounce the two different. And I guarantee 99% of non-linguist native speakers would - even after saying words with each a couple of times - say that /iː/ and /i/ are pronounced exactly the same, despite them being considered different phonemes.