Looking at the English Phonology article, I felt that there wasn't any comprehensive coverage of the issue of whether the velar nasal consonant [ŋ] should be treated as a phoneme of English, or as an allophone of /n/. This may well seem a very minor old matter, but I think it's an interesting one. I also feel it's a nice simple example of what you can achieve with underlying phonological representations and ordered rules. I was going to add this piece to the Consonants section, but it was much bigger than any of the other notes on English consonants, and one Wikipedia editor suggested I should start a new section in English Phonology on Controversial Issues. So I did.
Having created a section on Controversial Issues, I felt it looked rather empty with only the velar nasal case to list. Looking around for other issues brought me to look again at the analysis of the English vowel system. I never cease to be surprised when I read that English has 20 or 21 vowel phonemes, especially when this statement is linked with a remark to the effect that this huge number of vowel phonemes makes English a very unusual language. I don't have a problem with saying that English (RP, at least) has a large number of vocalic nuclei, but that's not the same as saying it has a large number of vowel phonemes. So I have added a second section to Controversial Issues on alternative analyses of the English vowel system with fewer phonemes. Other editors have subsequently made improvements to what I wrote, and this has made the explanations clearer.
Finally, I realized that I had duplicated some material that I wrote for a different Wikipedia article, on the Phoneme. The piece in question is headed The non-uniqueness of phonemic solutions. I wanted to make the point that there are different ways of analyzing the phonemic system of a language. Since I had used the English vowel system and the velar nasal as examples, I decided to reduce the overlap with the newer material by slimming down the examples.
Any comments would be welcome.