I added diphthongs like aɪ and ɪə to Wikidata. I added them to groups of whether they are closing or centering.
I would also like to add them to group based on whether they are wide or narrow as I read that this is an additional property in which they differ. I however can't find a good list that defines which diphthongs are wide and which are narrow. Can someone point me to a good resource or give himself a list?
Rising and Falling
,Closing, Opening and Centering
,wide and narrow
andlength
.