The long OO-sound and short OO-sound

Table 1. 90 common words spell the long OO-sound with oo, but
             91 words spell it with other letters, in the stem of words and endings.
             And in some words oo spells a shorter sound, e.g. 'good' in table 2.

 Table 2. The short OO sound has ended up with no identifiable spelling of its own.
             All the spellings used for it (oo, u, oul, ou, o) spell other sounds too: 
             took - spook, flood; pull - dull, truth; should - shoulder, smoulder;
             courier - cloud, group, country; wolf - womb, women, wombat.

 book   brook cook foot good hood   hook look rook shook took stood whoosh
 wood wool

 bull   bullet   bullion  full pull bush butcher  cuckoo cushion  pudding  push pussy  put      shush sugar 

  could should would     courier     wolf woman                  [36 words]

For several reasons, the use of the letter 'o' was never properly standardised in
English. It first lost its reliable link to just one sound as in 'got hot', when early
scribes started to use it for the short U-sound whenever this occurred next to the
letters  'm', 'n', or 'u' leaving us with spellings likes 'come' ,'none' and 'love'. ('Love'
used to be spelt 'loue' until the introduction of v in the 17^th century. Until then 'u'
spelt both the short U-sound and the V-sound, e.g. 'under' and 'ouer') 
     The scribes made the 'O for U' substitution because they thought that too many downward strokes next to each other, as in 'sume, nune, luue' made reading difficult.
The O/U overlap became worse during the 16^th century when some English vowel
sounds appear to have changed slightly and some earlier spellings were re-used for
different sounds, but not systematically so.

     Some respellings made words more phonic:
honde – hand, londe – land, honger – hunger, trompet – trumpet,
roume – room, fole – fool, rofe – roof, rote – root, sone – soon, tothe – tooth.

     Other changes brought no phonic improvement:
bloud – blood, contre – country, shulde – should, toched – touched,
doth – does, whome – whom.

   Many re-spellings made things worse:
shues – shoes,  trueth – thruth,  frute – fruit, doo – do,
bothe – both,  onely – only,
doune – down,  toune – town

                           [with 'own' now also used in ' blown' and 'shown']
dout – doubt.