D'Odorico Laura, Jacob Valentina
Department of Psychology, University of Milano-Bicocca, Milan, Italy.
Int J Lang Commun Disord. 2006 May-Jun;41(3):293-311. doi: 10.1080/13682820500342976.
Children who have reached the age of 2 years without having acquired a 50-word vocabulary and/or who use no word combinations are referred to in the literature as 'Late Talkers'. Research has not yet identified the factors that cause slow development of expressive language; in particular, relatively little research has been carried out on the characteristics of the maternal linguistic input received by Late Talkers. In fact, the majority of studies in this area have focused principally on the mothers' semantic, pragmatic and interactive verbal behaviour.
The objective was to verify whether the input addressed to a group of Late Talkers differs to that addressed to a group of typically developing peers. It was expected that there would be differences in the prosodic and structural/lexical properties of the input, which by creating a 'less than optimal environment' for language acquisition processes, could affect the children's rate of linguistic development.
METHODS & PROCEDURES: The spontaneous maternal speech of nine Italian-speaking mothers of late-talking toddlers (LT) at 20 months of age was examined and compared with that of nine mothers of age-matched children with typical language development (Late Starters). Data were collected during video-recorded play sessions, which were transcribed and coded based on the structural-lexical and acoustical characteristics of the mothers' speech. Group differences were tested for the following variables: number of utterances per minute, mean number of words per utterance (MLUw), number of nouns per minute, number of different nouns per minute, common nouns as a percentage of overall words, type/token ratio for common nouns, one-word utterances as a percentage of the total number of utterances, one-word utterances formed by a common noun as a percentage of the total number of utterances, mean syllable duration, duration of the final syllable of the utterance, F0 maximum (the highest F0 in the utterance), F0 minimum (the lowest F0 in the utterance) and F0 range (by subtracting F0 min from F0 max).
OUTCOMES & RESULTS: The mothers of LT produced common nouns and mark nouns by a pitch peak with a significantly lower frequency than the mothers of the children with typical language development. The mothers of LT also used flat pitch contours more often than the mothers of the typically developing peers.
The study provides evidence that maternal input addressed to Late Talkers can contribute to slowing the process of language acquisition. Based on these findings, additional investigations that examine the contribution of maternal verbal behaviour to the development of language delay are warranted.
在文献中，2岁时词汇量未达到50个单词且/或未使用单词组合的儿童被称为“说话晚的孩子”。研究尚未确定导致表达性语言发展缓慢的因素；特别是，针对说话晚的孩子所接受的母亲语言输入特征的研究相对较少。事实上，该领域的大多数研究主要集中在母亲的语义、语用和互动言语行为上。
目的是验证针对一组说话晚的孩子的语言输入是否与针对一组发育正常的同龄人有所不同。预计语言输入的韵律和结构/词汇属性会存在差异，这会为语言习得过程创造一个“不太理想的环境”，进而可能影响儿童的语言发展速度。
研究了9名20个月大说意大利语的说话晚的幼儿（LT）母亲的自发言语，并将其与9名年龄匹配、语言发育正常的儿童（起步晚的孩子）的母亲的言语进行比较。数据收集于视频记录的玩耍时段，根据母亲言语的结构-词汇和声学特征进行转录和编码。对以下变量进行组间差异测试：每分钟话语数量、每个话语的平均单词数量（MLUw）、每分钟名词数量、每分钟不同名词数量、普通名词占总单词数的百分比、普通名词的类型/词次比、单词话语占话语总数的百分比、由普通名词构成的单词话语占话语总数的百分比、平均音节时长、话语最后一个音节的时长、F0最大值（话语中的最高F0）、F0最小值（话语中的最低F0）以及F0范围（F0最大值减去F0最小值）。
说话晚的孩子的母亲使用高音调峰值产生普通名词和标记名词的频率明显低于语言发育正常儿童的母亲。说话晚的孩子的母亲也比发育正常的同龄人的母亲更频繁地使用平调轮廓。
该研究提供了证据，表明针对说话晚的孩子的母亲语言输入可能会导致语言习得过程放缓。基于这些发现，有必要进行更多研究来考察母亲言语行为对语言延迟发展的影响。
