Kypchak rounding harmony

In one dialect of Kyrgyz, there's an asymmetry in the system of vowel-rounding harmony.

Kazakh

In Kazakh, the roundness feature was lost on non-first syllables (except for with so-called long vowels), but rounding harmony makes up for this:

• */bu/+/kün/ > */bügün/
• */bügün/ > /bügin/ (modern orthographic/underlying form)
• /bügin/ > [bügün] (rounding harmony creates modern spoken form)

Examples of rounding harmony working:

• /jüremin/ [jürömün]
• /köremin/ [körömün]
• /sordım/ [sordum]
• /buldım/ [buldum]

Examples of rounding harmony not working:

• /turamın/ [turamın]
• /bulamın/ [bulamın]
• /soramın/ [soramın] (Kg: ?[soromun])

Kazakh's vowel system

As best I can tell:

• ı
• i +front
• u +round
• ü +front,+round

—

• a -high,(+low?)
• o +round,(-high)
• e +front,(-high)
• ö +front,+round,-high
• ä +front,-high,+low

—

• features that spread: +front,+low,+round
• features that don't spread: -high

another possibility:

• ı
• i +front
• u +round
• ü +front,+round

—

• a +ATR
• o +ATR,+round
• e +ATR,+front
• ö +ATR,+front,+round
• ä -ATR,+front(,-high??)

—

• features that spread: +front,+round,-ATR
• features that don't spread: +ATR(?)

Discussion

The latter possibility as a description of Kazakh's vowel system is more elegant in some ways, and also accounts for the actual values for most of the vowels. Tatar's vowel system also makes more sense as an off-shoot of the latter system (which, presumably, is an off-shoot of the former).

That /ä/ can progressively change /e/ to /ä/ probably works in either system:

• /däl me/ > /däl mä/

Kyrgyz

• V > [+rd] / V_[+rd] C_∅ __
• except not a > o / u C_∅ __