Mantras are only endowed with transformative power if specified in initiation (dīkṣa) in the mouth of the guru. It is far from much right pronunciation, but fairly the facility with which the mantra is endowed that provides it reworking functionality. Cundī dhāraṇī or mantra also first appeared inside the Kāraṇḍavyūhasūtra: https://baglamukhi-shabar-mantra10876.blogdal.com/37407542/the-basic-principles-of-kali