* In the "words that begin with an n" category he didn't include the most famous example: orange, the fruit, which has an n in Persian and Arabic from which it was borrowed but lost it (http://en.wikipedia.org/wiki/Orange_(fruit)#Etymology)
* I used to think that baby was the actual word and babe was a corruption, turns out most probably it was just the reverse (baby < babe + y) (http://english.stackexchange.com/questions/44883/was-baby-or...)
* Somewhat related to the last category: Have you ever wondered why the initial sound in chair and chandelier are pronounced differently in English? There was a sound change in French, chair was borrowed before that change and chandelier, like many other French word that start with ch, after that change.
* According to OED the reason that some animal names have the same singular and plural was that they originally contained a long vowel, e.g. deer, sheep, fish. Turns out, horse was also in this group but after a sound change its vowel shortened, hence the -s plural now.