As far as I can tell, the proper name of the attachment is 'hook'. 'Tail' is a description, just like "i-bar", "h with stroke", "turned h", "small capital R", "turned y", and lots of others, rather than the mouthful "ulveolar front labial trill" they describe. Font creators are not that good in phonetics.

(On the other hand, I suspect the guys at IPA sometimes just make up characters as they write. "Anyone got dibs on a mirrored small capital upside down R? No? Okay, it's mine!")

You might be interested in this Wikipedia article on IPA naming conventions. The Unicode Consortium's name for a given character or feature doesn't always agree with the IPA's name.

The "tail" and "hook" are indeed the same thing (the feature that indicates retroflexion); you will probably need at least two versions, one for letters like ɖ and ɳ where the tail is an extension of a stem or leg, and another for ʂ and ʐ where the tail is an appendage to a horizontal stroke. If you need more fonts with IPA characters for reference, you could also look at Gentium, Charis SIL, Doulos SIL, and Andika Basic, all available from SIL.

Nice to hear you're putting IPA characters in your font!

They're both used to represent retroflex consonants in IPA.The old name of ɖ was "LATIN SMALL LETTER D RETROFLEX HOOK". I guess it was changed to "tail" to avoid confusion with ɗ, "LATIN SMALL LETTER D WITH HOOK".

ETA: too slow :)

I would add that this seems to be a dispute between descriptions based on appearance (hook) and on function (retroflex). If the possibility exists, I’d always prefer a functional description, but I don’t run the place, and there’s a lot of history involved.

I know we love our computers, but I would strongly advise buying a used copy of Phonetic Symbol Guide by Pullum et al.

—
Joe Clark
http://joeclark.org/

Pullum's is a great book, just perfect for typographers as it also contains brief descriptions of the history of certain character forms -- i.e., from which it was derived -- as well as alternative representations.

(But it's been a while since I last saw it -- is it indeed that book?)

thanks a lot for all the answers. it helped a lot.