One final example is the striking sex difference in the form of speech known as ‘motherese’. This is the very characteristic speech style that women use naturally when talking to babies. It has a high-pitched, very sing-song, melodious quality with exaggerated pitch contours, and is very repetitive. Babies find it calming. A study by Marilee Monnot showed that babies whose mothers spent more time speaking in this way gained weight faster and passed key developmental stages earlier.
