[Facts] Re: How do you get the pronunciation -lee from -leigh?
hmm, actually in Middle English the gh was NOT pronounced. It's purely a scribal convention to replace an earlier, archaic letter "yogh" ȝ, which represented the phonemes /j/ and /h/ when they were formerly represented by "g" in Old English (although there has been some assimilation of original "h" to "g" in the process). In early Old English palatised (front-of-mouth) g became indistinguishable from /j/, but rather than being spelled as /j/, both palatal g and earlier j were spelled as g (in Frisian the same assimilation occurred, but spelling usually became "j"). Final g following a vowel became either palatal /j/ or guttural /h/ (spelling of the latter varied between "h" and "g"). When preceded by an i, final g was sometimes lost and the i later changed to y for clarity when final (day v. daily), but when retained would be written in Middle English as ȝ, later "gh". The "i" in leigh is also a scribal convention, indicating the "gh" is either /j/ or silent, while the /e/ is pronounces i: due to "levelling" (not a diphthong as in eight and weight - ȝ need not be final and would still be usually replaced by "gh", although sometimes s or z are used in names, such as Menzies [menyes] or Dalziel [deeyell]).