Answer

Previously I posted about the code. Few people asked me about it. Okay, maybe it is not that easy.

sir ejo is an aboriginal cil
a word acdgk means BeforeCentury wars
you c aboriginal cil likes hl milk ad

hints: maths and right-left-right

right-left-right:
- People can differentiate left and right if there's at least a pair of items. For example: ab - a is at left and b is at right.
- Each of the sentence are in multiple of 2.
- There are 3 sentences and 3 items (right-left-right).
- Based on those, can try: pair up each word in the sentence and cross out the useless words.

right: sir ejo | is an | aboriginal cil
left: a word | acdgk means | BeforeCentury wars
right: you c | aboriginal cil | likes hl | milk ad

It becomes:
ejo an cil
a acdgk BeforeCentury
c cil hl ad

maths:
- The easiest way to convert words to numbers is by the position of the characters. a is 1 while z is 24.

It becomes:
5 10 15 ; 1 14 ; 3 9 12
1 ; 1 3 4 7 11 ; Left out the BeforeCentury for first
3 ; 3 9 12 ; 8 12 ; 1 4

- See the pattern? It's Fibonacci series number.
- For example: ejo = 5 10 15 -> 5+10 = 15 so the next number is 10+15=25
acdgk = 1 3 4 7 11 -> 1+3=4; 3+4=7; 4+7=11 so the next number is 7+11=18

It becomes:
10+15 ; 1+14 ; 9+12 = you
1 ; 7+11 ; = ar
3 ; 9+12 ; 8+12 ; 1+4 = cute

BeforeCentury:
- BeforeCentury doesn't follow the pattern of other words.
- Think of other hint: only 2 capitalized characters ever appeared.
- Take B and C only.

BC = 2+3 = 5 = e

So the answer is "you are cute".

***

Some people told me:
- He tried to multiple, add, divide, subtract the right character to the left character and to the right character.

Possible, but too complicated.
1st, there's are 4^3 combination for Operation Right; Operation Left; Operation Right
2nd, there are total of 20 words, 4^3*20 combination
3rd, it doesn't really make sense because some of the words have more than 3 characters

- There are many possible way to convert character to number, why based on position of the character?

It's the easiest way.

- How if I don't know Fibonacci?

It's okay not to know Fibonacci, you can just do it based on the pattern of the numbers just like most of the questions in IQ test.
For example: 1, 5, 9, ... the next number is? 13

***

Cheats:

- Find the weirdest word: acdgk
- Convert it to number
- Get the pattern
- Do it for all other words (If don't have idea about the Right-Left-Right)
- Cross out words that don't follow the pattern
- Get the answer

New one for people who's interested :P