When we think in a language other than our mother tongue, we are better able to think rationally and objectively because, while we concentrate on expressing our ideas in this other language, emotions are kept at bay. From this stems the theory that thinking in another language could help us to solve a problem at hand more efficiently or quickly.
Presumably, this implies that our level of fluency in this second language is good enough to cogitate, but not so good as to not be a challenge anymore. It also assumes that the issue we have in front of us be of a plain and logical nature, or that being purely logical is preferable to being human.
An interesting theory as far as understanding how the brain works is concerned, but would anyone actually consider using it as a problem-solving technique?
Read the article from businessweek.com.