New Vowel Phonemes for Diinlang

As has been seen in previous posts, English has a considerable number of vowel phonemes. Languages such as Spanish and Italian have considerably less. If Diinlang is to be accessible to persons other than native English speakers the number of basic vowel phonemes it will use needs to be considered.
To this end. I propose a system of twelve vowel phonemes for Diinlang. These correspond to the traditional short and long vowels of English, with a logical addition.
The short vowels are a, e, i, o, u pronounced as in the English words bat, bet, bit, bot and but. [bæt, bɛt, bɪt, bɒt, bʌt] e” also serves as schwa.
The long vowels are ay, ee, iy, oh, uu pronounced as in bait, beat, bite, boat, bute, which are rendered phonetically as bayt, beet, biyt, boht and buut. [beɪt, biːt, baɪt, bəʊt, buːt] The long vowels correspond to the phonemes sometimes rendered as ā, ē, ī, ō, ū. English learners are often taught the long vowels “say their name”, although in Diinlang ū will be more “uu” than “yu”.   It will be observed that two long vowels are written with “-y” and two are doubled. “ō” is the “exception”, being written as “oh”. “o” also combines with –y to give the basic vowel phoneme “oy” as in “boy” [bɔɪ]. “ou” is the phoneme [] as in “cow”, kou.
This system has some modifications to that used on earlier pages. “ee” replaces “ii”, creating words closer to more traditional English spelling practice.  It is pronounced like the “ea” in “east” [iːst]. The ambiguous “oo” of English is still avoided, being replaced with “u” or “uu”. “aa” will probably have an “ah” sound and should be respelled accordingly.
The “short” vowels and “-y” vowels combined with –r or –h create a number of vowel-like sounds.
When used in a terminal position the pronounciation of some short vowels may be modified in Diinlang:
–o” is pronounced “-oh”, regardless of whether the final “-h” is written.
-i” and “-e” will probably retain their short form pronounciation. Possibly these may be thought of as “ih” and “eh
-a” will probably be pronounced “-ah” in the terminal position, as in the Spanish “señora”.
-u” will probably be pronounced as “-uu” in the terminal position, as in English words such as “kudzu”.