“however, the ability the think in multiple languages does give a person a cognitive advantage”
How does this work? Does it increase as more languages are added, and (as I would guess) does the divergence in the structure (say, english and mandarin together compared with spanish and portgues) of the 2 languages impact the cognitive skills?
Agreed. The manner in which an individual conceives an idea and perceives the environment is definitely colored by linguistic experience. Cultural idioms tied to a language also have an influence.