Google: "study shows unborn child can learn language in womb"
One of many research done on the subject:
University Of Florida Research Adds To Evidence That Unborn Children Hear 'Melody' Of Speech
This is a report on a study of intelligibility of sound
"They implanted an electronic "pickup" inside the inner ear of a fetal sheep, then played 64 recorded sentences on a loudspeaker in the open air near the mother sheep. The sounds the pickups detected were recorded and played back to 30 human adult listeners"
The coclusion of the study:
"The listeners understood all of the sentences recorded in the open air, ... and about 30 percent of the sentences recorded in the fetal sheep's inner ear."
Nothing about enhancement of language acquisition.
I wasn't arguing that sounds couldn't be heard. It's the second point that I'm really questioning here, that language, different from the child's mother, can be acquired/learned and/or have a lasting impact on an unborn child's ability to acquire a second language.