>If consciousness is a psychological development induced by specific linguistic features, then what are those features? Are people capable of consciousness if they can only speak an insufficiently advanced language?

Developmental psychology has alot to say on this topic. For one you need the linguistic structure of "I" and pronouns in general(I/We/It). Pronouns are a universal linguistic structure and represent the ability to shift between 1st, 2nd, and 3rd person perspective. A pretty amazing cognitive ability if you think about it.