Well, the -ly of “duly” is originally from the word “like”, though far back enough that it would have used something similar to the vowel it uses now.
July comes from the Latin name Iulius, same FLEECE vowel. Here’s what etymonline ( http://www.etymonline.com/index.php?term=July ) has to say about July:
‘July ; seventh month, c. 1050, Iulius, from Anglo-French julie […] Accented on the first syllable in English until 18c.; “the modern Eng. pronunciation is abnormal and unexplained” [OED].’
So, it did rhyme with duly until the 1700s, and nobody knows why it changed, but we do know that the difference isn’t for any historical reason.
Why would you say that? Merriam-Webster (correctly) says that “brother” traces back through Old English, not Greek (see here: http://www.merriam-webster.com/dictionary/brother ). See also http://etymonline.com/index.php?term=brother , pointing out that as far as we can trace the language back, the word for “brother” has always been “brother”, right back to the proto-indo-european root (“bhrater”).
Saying the English word “brother” comes from Ancient Greek is like saying you’ve inherited your nose shape from your aunt.
Well, the -ly of “duly” is originally from the word “like”, though far back enough that it would have used something similar to the vowel it uses now.
July comes from the Latin name Iulius, same FLEECE vowel. Here’s what etymonline ( http://www.etymonline.com/index.php?term=July ) has to say about July:
‘July ; seventh month, c. 1050, Iulius, from Anglo-French julie […] Accented on the first syllable in English until 18c.; “the modern Eng. pronunciation is abnormal and unexplained” [OED].’
So, it did rhyme with duly until the 1700s, and nobody knows why it changed, but we do know that the difference isn’t for any historical reason.