Yes, it's strange. YES, the "wild" part of "wilderness" means the same thing as the word "wild," but "wilderness" has a short "i" like "will" and "wild" has a long "i" like "why." And here's another puzzle: there is a perfectly good word, "wildness," that uses the long "i" like "why." "-derness" doesn't have a meaning. "-ness" has a sort of meaning but I can't explain it. I'm not enough of a scholar to tell you the history or background behind the words, but I can give you at least one other examples of a similar construction: "The hinterlands" (short i) are remote regions, far from towns, regions that are _behind_ (long i) the populated areas. Also, "yonder" means that big vague area way off in the distance over there. I almost have to wave my arm when I say that! It is related to the words "yon" and "beyond." No pronunciation difference, no "-ness," but there's that same "-er" suffix.

it's definitely will'der'ness derness on its own doesn't mean anything, but 'ness' is often used as a suffix which kind of transforms a noun into an abstract concept e.g. nothing - nothingness, meaningless - meaninglessness. I'd guess that Wild was once spelled 'wilde', meaning that the transformation was wilde -> wildeness. It might once have been pronounced wild'nessm, but if you add the addition of the R leaves it very clear to me that it must be pronounced will - der - ness

A quick google suggests that there is another word hidden in there. wilderness comes from old English, meaning Wild + deer + ness, and is used to mean 'a place inhabited by wild deer (or more generally wild animals). wildness on the other hand, is an noun describing the extent to which a person or thing is wild. Therefore, the Suffix +ness is used to transform an adjective into a state of being or a noun. My daughter recently learned a pronunciation rule which might help you. My daughter calls it 'the magic E' :) Vowel + consonant combinations are usually pronounced with the 'sound' of the vowel. However, where the combination of vowel + consonant + e exists, the vowel is pronounced like the name of the letter. For example 'i' in kit is 'ih', but the 'i' in kite is 'eye', Rid is 'R + ih + d', but ride is 'R + eye + d'. So to look at your original question, the 'i' sound is 'ih' and not 'eye' because there is no 'consonant/e/ directly afterwards. Hope it helps.

in order to get the pronunciation, i will break it down for you : will - der - ness