Hello and welcome to this interview today that we are doing. We are very honored to have with us Professor, Doctor Claartje Levelt. She's a professor of First Language Acquisition at Leiden University. And she's going to introduce yet another field in linguistics that has a lot to do with experiments. So, we're very anxious to hear about that. Within this bigger field, could you explain what it is that you specifically are looking into? >> Yeah, I'm mainly focused on two things. One is phonological acquisition so how do children acquire the sound structure of their native language and the other topic is learning mechanisms. So, what are the learning mechanisms that babies bring to the task of acquiring their language. >> So, the phonological structure of a language. >> Yes. >> So, that means that they have to recognize the sounds and then, know what sounds are used where, something like that? >> Yeah, you could ask the question, how do they acquire the sound inventory of, of his or her, of their native language. So but what I do is I focus on, on their early word productions. >> Mm-hm. >> So they when they, when they are around one year old, they start to produce their first words usually, babies. And and then they say more and more. And but their first words, they sound very different from the way we would produce those words. So for example they, they would say guck for duck or tike for strike or, oo for shoe, something like that. So, they make a lot of mistakes >> Yeah. >> They're not real mistakes, but [LAUGH], they, they their word forms deviate from what we would do. >> And. >> Yeah? >> And how do, why do these deviations occur? >> Yeah, so that's the big question. Yeah [LAUGH]. So they're, and, and there's many possible answers so it's, it's it's quite difficult to find why they do that. Because they have to acquire a lot of different things. So, for one thing, they have to acquire the phonological grammar of their language. And so it could be that they make the mistake because their grammar does not allow the specific structure that they have problems with yet. >> Mm-hm. >> So that, that's one possibility. But then on the other hand, they are also they also have to produce the word. And for that you need speech production mechanism. >> Mm-hm. >> So how does that mechanism work? >> Yeah, it works, so what, what you have to do, so for example, when you, when you name a picture, so you see a picture of a cat and you have to say, cat. What you do is you find the words that is, that refers to that object. And you find the sounds that are stored for that word. So, for cat you'd find k, a, t, or, c, a, t, when you use the, the, the letters. And so you retrieve the sounds then you organize those sounds into a bigger unit, a syllable-like unit. And then you start to build a motor program for that, for those sounds. And when you have built the motor program that motor program is sent to your nerves and though, and they and, and the motor program is in the end executed by the articulators. Yeah. So, and it's a very fast process. So when an adult names a picture, you do that in like 600 milliseconds, so it is a very fast process. But, it also means that a lot of things can go wrong because you have, you have to retrieve the words, you have to retrieve the sounds. And to retrieve the sounds you, you have to have stored those sounds in, in your memory and that means that you have to, you have perceived the sounds. You need to have perceived the sounds, and stored those sounds in, in your memory. >> So how do you investigate these different stages? How do you find out? >> Where something went wrong. >> Yeah, yeah. So that's the big question. And I, I don't have the real final answer to that, of course. But there's a lot of cues that you can use to find the answer. So, for example, some errors are really very systematic. >> Okay. >> And occur always. And you can really predict that when you ask the child to say this word, that, that specific error will occur. Other errors are much more variable. So, if an error is really systematic, there is so, it could be a, an error due to grammar, because grammar, of course, gives you very systematic things, and, as, and you can... So, that, that's one possibility. But, it could also be that the lexical representation is contains an error. Because then, in that case too, you would get a very systematic error. >> What kind of error could that be? Could you maybe give an example of an error with a lexical representation? >> Yeah, so for example, if you have not really perceived a word, a word in all detail. >> Okay. >> So for example, you hear the word strike for the first time. >> Mm-hm. >> And then you store something like tike maybe because the str [LAUGH] or the s and the r disappeared a little bIt. Yeah, because as a, when you're a baby, processing things takes a lot of time and takes more effort. So, in the end, you've stored tike instead of strike. Now that means that when you want to produce the word, you don't have the s and the r, so you will not produce them. And you would produce tike. >> So, many thanks today to our guest Professor, Doctor Claartje Levelt. We of course invite you to go onto the forum and discuss what you've heard today and Professor Levelt also has a final question for you. >> If you have a baby at home or in your environment and you're interested in language and language acquisition, you could keep a diary of the language acquisition of your baby and study the data. And if you find any interesting patterns post them on the forum and we'll react to that.