The Complete Guide to English Spelling Rules

(^) Nor are there many words that end in il. If we exclude words that contain the diphthongs oi and ai (oil,
soil, ail, tail, etc.), we are left with about three dozen words:
(^) Note that all the words in this group have a single l. When a suffix that begins with an l is added, it only
appears that the l has been doubled.
(^) Many dictionaries offer duffel bag and duffle coat on the same page. Since there are no fel words in
English, both words should follow the spelling rule—duffle bag and duffle coat.