Substance in Chinese I'm working through some material. I'm coming from an English/Latin perspective towards understanding this.

Looking at the following translations

材料 - material - cáiliào

物料 - materials - wùliào

Is the first character a form of modifier? I'm a bit confused because liào(料) seems to also translate as material.
Mandarin has relatively few distinct sounds (about 1300) and each character corresponds to one of those sounds.  The language has tended toward more disyllabic words to reduce ambiguity.  Often these words consist of two characters whose meanings are both close to the meaning of the whole.