This study explores the potentials and restrictions of sociolinguistic research on language shift. It discusses how social psychology might prove more succesful than sociologically-based correlational-global analysis methodology, if, at least, two necessary conditions are fulfilled. On the one hand, a mere additive consideration of ‘subjective’ psychological factors in addition to the ‘objective’ factors of language shift is not sufficient. On the other hand, sociolinguistics has to show more care in handling terms, notions, and theories borrowed from social psychology in a methodologically more accurate way than evidenced by current research practice.