Supposedly resulting from abnormal antenatal exposure to hormones, this cluster includes maleness, homosexuality, left-handedness, poor visual-spatial skills, immune disorders, and perhaps also language-learning talent.

ECONOMIST: What makes some people learn language after language?

While a study is currently in progress at this point in time with the same research group linked below, specific to those with autism spectrum disorders, the linked research suggests that language development delays in the general population are associated with high levels of prenatal testosterone among males but high levels of prenatal testosterone among females provides a protective effect for language development.

FORBES: Is Being Female Protective Against Autism?

Research into how babies acquire language skills could someday further understanding of how development goes awry, allowing for earlier treatments of disorders such as autism, says Dr. Kuhl.

WSJ: Wise Beyond Their Years: What Babies Really Know