Language Enrichment for the Unborn Activities to Connect and Stimulate Language Development It is not a myth that babies can hear and process speech even before birth, particularly when it comes to the mother's voice. In fact, they are capable of slowing down their heart rate and experiencing a sense of calmness as a response. Interestingly, this effect is more pronounced when the mother speaks her native language as opposed to a foreign language. Many of us have directly or indirectly experienced the soothing effect that a mother's voice can have on an unborn baby and later on a newborn.