Develop a metric or mapping of vowel similarity

[emo-eth]

In order to support vowel-partner rhymes (HID -> HEED), we need to determine which vowel sounds are more or less similar to each other. A good starting point is finding the formants of the vowels in the CMU dict.
This is blocking for all of the vowel partners work.

[emo-eth]

A MetaVowel class with custom comparison methods would suit this process well. For example, diphthongs can be comprised of their individual phones which can be compared against those of other MetaVowels. This would also allow phones to be overridden for dialects other than the CMU Pronunciation Dictionary's regional Northeastern American English, and more or less strict vowel similarity metrics.