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Lexical and Grammatical Abilities in Deaf Italian Preschoolers: The Role of Duration of Formal Language Experience


Drs. Pasquale Rinaldi and Maria Cristina Caselli (Institute of Cognitive Sciences and Technologies, Rome, Italy) were available from 2/22/10 to 3/14/10 to answer questions and share ideas concerning their research and its implications for parents of children who are deaf/hard of hearing, their teachers and other professionals who work with them.

You are encouraged to read the research summary below and review the attached discussion.


Around 95% of deaf children have hearing parents, most of whom are unfamiliar with sign language. These children have consistently revealed a general delay in the onset of language, as well as a slower rate of progression, resulting in poorer linguistic abilities with respect to same-age hearing children.
So as to compensate for their difficulties in speaking, deaf children, and hearing children with linguistic disabilities in general, rely more on the use of gestures than their peers do. In this light, some language education and/or rehabilitation programs for deaf children rely on simultaneous communication, which consists of the spoken language and the simultaneous use of lexical signs from the sign language used in the given country, yet following the grammatical structure of the spoken language (in Italy, this form of communication is referred to as “bimodal”). The supporters of simultaneous communication claim that the use of a visual-gestural modality, which is not impaired in deaf children, may improve the acquisition of spoken language. Studies on the effect of the use of manually coded systems (mostly MCE) on language acquisition in deaf children with hearing parents show discordant results. In Italy, no studies have evaluated the effects of the bimodal method on language acquisition in deaf children, although there are clinical case reports that show that this method has positive effects.

Among the most important factors related to language development there were age at diagnosis of hearing loss, age at beginning language rehabilitation, and the child’s general intellectual skills. To the best of our knowledge, no studies have compared deaf children with traditional hearing aids to hearing children matching the two groups in terms of the duration of exposure to language, which for deaf children begins with the start of formal language rehabilitation and for hearing children begins at birth. Instead, this method has been used to assess language development in deaf children with a Cochlear Implant (CI). The main objective of the present study was to assess language development of deaf children without a CI, considering the chronological age as well as the time elapsed since beginning formal language training. The specific goals were to evaluate language skills in deaf Italian preschoolers, compared to hearing children, taking into account both chronological age and duration of formal language training, to meet the following three main objectives: 1) to evaluate spoken vocabulary and early grammar skills; 2) to evaluate the effects of different rehabilitation methods (i.e., the oral method vs. the bimodal method) on language abilities; 3) to evaluate the rate of progression of language development with age.
The importance of the results lies in the fact that in Italy, as in other countries, almost all children with severe or profound hearing loss undergo speech therapy programs and the linguistic capabilities acquired through this training often constitute one of the criteria for deciding whether or not the child should receive a CI.

We collected data on language development from deaf preschool children without cognitive or neurological deficit associated with deafness. All of the children had a hearing aid and attended speech therapy sessions; half of them were taught with the oral method (speaking without systematically using gesture and/or signs) and other half with the bimodal method. None of the parents knew Sign Language before discovering that their child was deaf. As controls, two hearing children were individually matched with each deaf child: one with the same chronological age; the other one whose chronological age corresponded to, for the deaf child, the amount of time that had elapsed between starting a speech therapy training and the time that the questionnaire was administered. This time was considered as the duration of formal spoken language experience (for hearing children language experience begins with birth).

To evaluate the differences in vocabulary and grammar in relation to the duration of language experience, deaf and hearing children were subdivided into two subgroups, according to the duration of spoken language experience: “shorter”, with 8-17 months of experience, and “longer”, with 18-44 months of experience. We are aware that when deaf children begin formal language training, they probably have already been exposed to language and have some communicative and linguistic experience. However, given that exposure is mainly auditory for deaf children with hearing parents, uptake is probably quite low until formal language training begins. To evaluate language development we adapted for our purposes the short form of the Italian version of the MacArthur–Bates CDI, Words and Sentences.

The results showed that preschool deaf children, compared to same-age hearing children, have a significant delay in both vocabulary and grammar.
When comparing language development in deaf and hearing children with comparable duration of language experience, we found no differences, indicating that the duration of formal language experience is an important element which should be taken into consideration when evaluating deaf preschool children’s spoken language abilities.

Deaf and hearing children with comparable duration of language experience were also similar in terms of the use of non-verbal modalities: signs and/or gestures were used to “name” events or objects for which the child did not know the corresponding word. In both deaf and hearing children, this behavior was closely related to the development of spoken vocabulary: the number of signs/gestures produced decreased with increasing lexical repertoire.

We found no differences between deaf children exposed to the bimodal method and those exposed to the oral method, in either vocabulary or grammar. However, the lack of significant differences could be due to the small number of participants in each subgroup. Nonetheless, our data show that the deaf children exposed to the bimodal method tended to understand and produce more words, which could indicate that the use of visual-gestural modality does not hinder the learning of the spoken language and that it can instead constitute a useful means of support for learning to speak. In fact, children exposed to the bimodal method tend to use more frequently the gestural modality to express new meanings for which they do not know the corresponding word, as well as meanings for which they do know the spoken word.

The similarities between deaf children and hearing children with a similar duration of formal language experience could suggest that these groups undergo similar “phases” in language development. The increases in language development with increasing duration of language experience were quite evident for the hearing children and much less evident for the deaf children. This could be due to the fact that hearing children are exposed to the spoken language not only when it is specifically directed at them but also when others around them are speaking (e.g., their parents or other adults and other children), in what could be referred to as a “natural” context. Instead, deaf children are only exposed to language through face-to-face interactions and undergo a long, slow, arduous process of formal exposure, consisting of a highly-structured didactic processes.

With regard to the clinical implications of our findings, in terms of language education for deaf children, these data could help speech therapists and teachers in planning interventions that combine gestural modality with speech, so as to improve the language capabilities of deaf children. Moreover, measurements similar to that of “time post-implant” used to evaluate the effectiveness of the CI could be very useful in understanding the effectiveness of speech therapy also for deaf children with the traditional hearing aid, to determine whether the progress made is consistent with expectations based on the duration of formal language experience. In fact, this information could help clinicians to decide whether or not to change the type of hearing aid and/or the type of language education and to decide whether or not the child is a candidate for a CI.

The delay in linguistic development in deaf children, compared to same-age hearing children, may in part be attributable to less language experience (and not to deafness itself). In this light, we suggest that the language abilities of deaf children be evaluated in a different perspective: instead of estimating deficiencies compared to hearing children, deaf children should be evaluated based on their linguistic experience and cognitive and communicative potential.


Rinaldi, P., Caselli, M.C. (2009). Lexical and grammatical abilities in deaf Italian preschoolers: The role of duration of formal language experience. Journal of Deaf Studies and Deaf Education, 14(1), 63-75.