The /�/ vowel is spelled <a> followed by two consonants or by one consonant in a monosyllable. The normal spelling of the /ʊ/ vowel is <oo> or <u> but there is also <ou> in should.
The sounds are both short but are well separated in the mouth and so should not cause problems for learners.
Interesting pairs include:
lacquer looker
palette pullet
The mean density is 0.9%. The set makes 28 sematic contrasts giving a semantic loading of 48%.
baccy bookie back book backed booked backing booking backings bookings backs books bally bully bash bush bashes bushes bract brooked cad could camel kummel carrier courier carriers couriers crack crook cracked crooked cracking crooking cracks crooks fat foot fats foots fatted footed fatter footer gad good gads goods hack hook hacked hooked hacking hooking hacks hooks had hood knack nook knacks nooks lack look lacked looked lacking looking lacks looks lacquer looker lacquers lookers pad pud padding pudding pal pull pals pulls palette pullet palettes pullets palled pulled palling pulling pally pulley pat put pats puts patting putting patch putsch patches putsches rack rook racked rooked racking rooking racks rooks shack shook shad should tack took
Credit: John Higgins