The core of the rhyming scheme is assonance:
assonance: matching vowels. (shake, hate) Assonance is sometimes referred to as slant rhymes, along with consonance.
Eminem is deliberately bending the pronunciation of each word so that they sound similar. This moves the vowel sounds of each rhyme into an assonance rhyme. An example of how "orange" in particular breaks down:
- "four inch" (assonance due to the g vs ch)
- "door hinge" (perfect/feminine)
- "storage" (assonance due to the ng vs g)
- "porridge" (assonance due to the ng vs dg)
- "George" (assonance due to r vs g and ng vs rg)
One thing of note is that rap tends to also care about how the sounds are spread throughout a sentence. If you break out the common sounds (using Eminem's pronunciation) you get something like this:
- Oh as in Orange, four, door, stOrage, pOrridge and GeOrge
- Ih as in orAnge, inch, hinge, in, storAge, porrIdge, with, GeoRGe
- R as in orange, four, door, storage, porridge, George
- Ndg as in orange, inch (almost), hinge
- Dg as in storage, porridge, George
Giving these letters and blanking out the uncommon sounds you get this (letters are vowels, numbers are consonants):
x xxx xx A1B2, xA1 B2, xA1 xB2, Bx xA1B3, xx xx xA1B3 xBx 3A1B3.
The rhyming pattern itself shows a more interesting overall pattern that essentially repeats A1B2 (oh-r-ih-ndg) three times and then switches to A1B3 (oh-r-ih-dg). This is the kind of thing Eminem is known for.