It depends what you're going for, really. Personally, I would either (a) extend the length contrast to more vowels or (b) eliminate it completely (unless of course I could come up with some really compelling reason for why it should have developed in only one vowel).
Okay. What would be entailed by those options? As in, all of the vowels would have a long and short version, or none would have them?
I've gone through some of the options already. You could still have quality contrasts, but these would be the surface realisations
of underlying contrasts in quantity. (E.g., /iː/ and /i/ realised respectively as [ i] and [ɪ].)
Keep in mind that phonemes are merely abstractions. In English, I've seen the vowel of go
phonemecised as /o/, /oː/, /ow/, and /oʊ/. It doesn't really matter which one you use as long as it's consistent with your overall analysis of the vowel system. One reason to prefer /oː/, for instance, is that there are some dialects where this sound really is
[oː] whereas other realisations--such as RP [əʊ] or the [ɵʊ] found in many North American varieties--clearly developed from this. On the other hand, using /ow/ makes it easier to write rules about which vowels appear where (such as before /r/). There's no single optimal solution.
If you want to have length as a contrastive component of your vowel system, it should probably be there for most if not all vowels. But you don't need to have a phonemic
length contrast in order to have phonetically
long vowels. You could still have both [æ] and [æː], just not in the same positions. (For instance, [æː] appears before a single consonant and [æ] when the syllable ends in more than one.)
Hm. I'll make an edited list with the vowels fixed, but here's some sounds:
xlt-/xɔlt/-like "cult" with a west-coast accent.
I'm not sure what you mean by "West Coast accent". In most of Southern California, for instance, /ʌ/ (the vowel of "cult") is being shifted towards [ɛ]. (A feature of the so-called California vowel shift
.) A shift toward [ɔ], on the other hand, is characteristic of the completely distinct and incompatible Northern Cities shift