The learning capacity of infants is a source of constant amazement. We know that babies are already developing language recognition abilities while still in the womb but until recently we never understood just how significant, and permanent, early language learning actually was.

A recent study by language scientists from Radboud University, Western Sydney University and Hanyang University has shown that babies begin learning and storing speech earlier than previously thought. Their paper, published in Royal Society Open Science, indicates that language learning in the first six months of life is subconsciously retained even when a child is raised to speak an entirely different language.

The experiment studied 29 Korean-born Dutch speakers. All 29 subjects were adopted by Dutch parents at ages spanning 6 to 17 months. These adoptees were all raised as Dutch speakers having never learned their native language, and across a two-week period they were taught to identify and reproduce a series of Korean consonants. The distinction between Dutch and Korean was key to the study, as all the Korean sounds taught were notably unlike any natural sounds from the Dutch language.

The adoptee's attempts to rearticulate the Korean consonants were rated for accuracy by Korean listeners against a similar sized control group of native-born Dutch speakers. The results were incredibly clear, the Korean adoptees rate of learning, and ability to correctly pronounce the foreign sounds, significantly surpassed that of the control group. This was despite any of the adoptee group having ever learned or spoken Korean.

Most interestingly, the study found no difference in the results of the adoptee group between those adopted under six months of age and those adopted after the age of seventeen months. This observation highlights the significant language learning that occurs in the first six months of life, regardless of whether it turns out to be the dominant language spoken.

"This means that even in the very early months of life, useful language knowledge is laid down, and what has been retained about the birth language is abstract knowledge about what patterns are possible, not, for instance, words," explains Mirjam Broersma from Radboud University.

This evidence follows on from another recent study that examined a group of Canadian teenagers who were adopted as babies from China. These adoptees were raised with French as their only known language, but using functional MRI were seen to have similar brain activation to native Chinese speakers when exposed to Chinese linguistic elements. This was despite only being exposed to the the language in the first twelve months of life, and never learning or speaking it.

The revelations from these studies highlight the importance of talking to your babies as much as possible throughout these early stages of life. The results also show that information learned through languages spoken to a baby are retained by the subconscious later in life, even when the child is raised speaking a completely different language. This hidden retention could help the individual to (re)learn their birth language later in life, and also sheds a fascinating insight into how we acquire language.