LENA

[Brian MacWhinney]

Dear Info-CHILDES,

Some people have been asking about the LENA system.  There is now an  
article about it on www.nytimes.com.  It was written by Yudhijit  
Bhattacharjee who is  a writer on the staff of Science magazine.  It  
is a pretty informative article and the reporter did a good job.  It  
may be difficult for people to locate the article and, since this  
could be potentially interesting for child language research, I am  
making a copy here.  However, you should be able to access it also by  
going to www.nytimes.com, subscribing and then looking for "LENA".   
The following is from the article.

-- Brian MacWhinney

The early days of parenthood are filled with anxiety. Parents fret  
over whether their babies are eating enough, growing enough and  
sleeping enough. As the children get a little older, parents also  
worry if they are talking enough.

But how do you judge a child’s language skills? Infoture, a Boulder- 
based company, aims to take the guesswork out of that question by  
selling a kind of verbal thermometer. The device, which costs $400, is  
called LENA (for “language environment analysis”), and here’s how it  
works. A voice recorder tucked into a child’s clothing records all the  
sounds in the environment. At the end of each day, special software  
evaluates both the amount of exposure the child has had to verbal  
stimulation as well as the child’s own utterances. Ultimately, the  
device generates percentile rankings that help assess a child’s  
language development, just as doctors provide such rankings for a  
child’s height, weight and head circumference.

Whatever its merits, LENA represents a radically new way of assessing  
language development. Doctors initially judge a child’s skills by  
asking parents about what a child can do. Kids with clear difficulties  
are referred to a speech pathologist for a more detailed evaluation.  
By contrast, Infoture would allow parents to monitor their kids more  
precisely and on their own. But is LENA necessary? Some linguists  
worry that the technology is more likely to raise false anxieties than  
to assuage genuine ones.

The man behind the vision, Infoture’s founder, Terrance Paul, has made  
a fortune selling software to assess children’s reading skills. His  
current venture was inspired by a well-known 1995 study that found  
that professional parents uttered more than three times as many words  
to their children as did parents who were on welfare. The children in  
the less talkative homes turned out to be less verbal and to have  
smaller vocabularies. Other studies have suggested that these gaps  
affect later professional success.

One way to close the language gap, Paul reasoned, would be to make  
early assessments of a child’s language world. Parents, he figured,  
could use the feedback to intervene and enrich their kids’ verbal  
environment as needed.

But how to build the ultimate baby monitor? The company’s engineers  
soon found that conventional speech-recognition software was not up to  
the task. The sounds a baby might encounter — a raspy grandparent, a  
TV commercial, a sibling’s chatter — were simply too varied to analyze  
successfully. The best solution, it seemed, was to eschew the  
identification of particular words and focus on a recording’s acoustic  
features. Modeling every conceivable sound in a household, they  
designed a system that distinguishes different voices from one  
another, gives a rough count of the number of words directed at a  
child and counts also the number of conversational “turns” that are  
taken as child and interlocutor exchange words. In future versions,  
the system may also include a measure called speech entropy, which  
represents the increasing complexity of a child’s speech as new  
consonants, words and phrases are added to its repertory.

On the basis of recordings from 314 families, Infoture engineers claim  
that the number of conversational turns and the entropy measure track  
closely with language ability as determined by speech professionals.  
Children with diagnosed language delays, for example, have lower  
entropy scores than children of a similar age who are developing  
normally. But the method has its critics. Tom Roeper, a linguist at  
the University of Massachusetts, Amherst, points out that measures of  
conversational turns and the like can’t reflect a child’s mastery of  
syntax. Learning to speak isn’t just about speaking frequently; it’s  
also about knowing how to put the right word in the right place.

If a device like LENA became popular, it might create new benchmarks  
for speech development. Mabel Rice, a speech pathologist at the  
University of Kansas, speculates that parents might direct repeated  
questions to their children in order to score more conversational  
turns. The focus on quantity could also reinforce cultural biases  
against quieter and perhaps more thoughtful kids; consider Albert  
Einstein, who was late to start talking. Even so, Rice says, pressure  
on parents to spend more time conversing with their children could  
have a positive effect. Partha Niyogi, a computer scientist at the  
University of Chicago and an adviser to Infoture, agrees. LENA, for  
him, is best understood as an early-warning system. “Suppose you are  
talking a lot to your child, but your child is talking very little,”  
he says. “It could be a sign of something wrong.”


--~--~---------~--~----~------------~-------~--~----~
You received this message because you are subscribed to the Google Groups "Info-CHILDES" group.
To post to this group, send email to info-childes at googlegroups.com
To unsubscribe from this group, send email to info-childes-unsubscribe at googlegroups.com
For more options, visit this group at http://groups.google.com/group/info-childes?hl=en
-~----------~----~----~----~------~----~------~--~---