Which language is more valuable in multilingual societies? – a question of dominance and power?

There have been many discussions as to which languages should be taught in school.

It may be argued that the more widely spoken languages are functionally more valuable in multilingual societies compared to minority languages. However, shall language really be used as a tool of power and dominance whilst cultural heritage and identity is being lost? The example below is a recent discussion addressing this issue in East Timor:
http://intercultural.humanities.manchester.ac.uk/?p=1392