To address the possible allophony of these phonemes in the late medieval northwest Midlands, one might look to McLaughlin's graphonemic system for the Pearl manuscript (McLaughlin, A Graphemic-Phonemic Study, 134-40) to argue that the resultant phoneme may have sounded closer to /u:/, given its striking number of allographemic options as both short and long vowel, <v, v-e, vv, v3 o, o-e, oo, ow, ov, o3, oe>, in comparison to those similarly available for /o:/, <o, o-e>.
The model of analogy described above, on the other hand, calculates all cases of allophony on the basis of stored memory traces.
How could children subconsciously and effortlessly intuit the kinds of generalizations about allophony (which are often complex and abstract) that many intelligent graduate students of phonology have a difficult time formulating?
Another strength of the book is the scrupulous attention to detail provided in the description of the phonological and morphological features, notably with regard to the treatment of vowel quality, rules of allophony, and syllable structure.
In a work like Dieth (1932) or Zai (1942), where there are many words for a given vowel class, the isolative reflex and any allophony shines through--and usually gives simpler patterns than LAS3, where there are sometimes strange patterns of apparent allophony that do not involve natural classes (Johnston 2000).