She found that all babies have this secret language, and if you respond to it within the first 0 - 3 months they will continue to make the sounds to communicate. If the sounds arn't recognised and responded to they lose this 'language' and every cry begins to sound the same.
Hopefully people understand what I am saying here - but this bit of info - that if you do not respond to the baby's needs, leading to them stopping trying to communicate - this is not explicityly linked to whether the caregiver knows the "baby language" or not. Whether they know the baby language or not, the baby's needs will be met by an attentive parent, hence the "language" and an attempt to communicate, would continue. If you ignore their needs, not relevant to whether you knew the "language" or not, they will stop trying to communicate...
I think that what she found there is evidence that babies need their needs met. And she found that the Baby Language can help you to do that, rather than knowing the language being what caused the language to continue in itself.
Do you get what I mean?
ie how would the baby know whether you know the "language" or not? They only know whether you respond to their needs or not.
That could also be evidence that not meeting a baby's needs effects their language and communication skills. Was this a proper study does anyone know?