Comparing the productive vocabularies of grey parrots (Psittacus erithacus) and young children.

Due to their outstanding ability of vocal imitation, parrots are often kept as pets. Research has shown that they do not just repeat human words. They can use words purposefully to label objects, persons, and animals, and they can even use conversational phrases in appropriate contexts. So far, the structure of pet parrots' vocabularies and the difference between them and human vocabulary acquisition has been studied only in one individual. This study quantitatively analyses parrot and child vocabularies in a larger sample using a vocabulary coding method suitable for assessing the vocabulary structure in both species. We have explored the composition of word-like sounds produced by 21 grey parrots (Psittacus erithacus) kept as pets in Czech- or Slovak-speaking homes, and compared it to the composition of early productive vocabularies of 21 children acquiring Czech (aged 8-18 months), who were matched to the parrots by vocabulary size. The results show that the 'vocabularies' of talking grey parrots and children differ: children use significantly more object labels, activity and situation labels, and emotional expressions, while parrots produce significantly more conversational expressions, greetings, and multiword utterances in general. These differences could reflect a strong link between learning spoken words and understanding the underlying concepts, an ability seemingly unique to human children (and absent in parrots), but also different communicative goals of the two species.

How to Build a Communicative Development Inventory: Insights From 43 Adaptations.

PURPOSE: This article reviews 43 adaptations of the MacArthur-Bates Communicative Development Inventories (MB-CDIs), a tool used for measuring children's communicative and language skills. The aim is to provide an overview of different approaches to develop local versions of the instrument (reflecting linguistic and cultural specifics) and to formulate recommendations and suggestions that expand the current guidelines of the MB-CDI Advisory Board. The article also discusses cross-linguistic differences in the structure of this tool, as well as the availability of sources for the language-specific MB-CDI adaptations. CONCLUSIONS: Strategies differ in the construction of the inventory contents and in the norming phase, as well as in documenting reliability and validity. The most frequent strategies in developing the item lists are translations of existing CDIs and pilot administrations; relatively recent strategies include consultations with child development experts. The norming approach varies in, for example, the number of participants and techniques of administrations. When establishing age-related norms, different methods of growth curve construction are used. We recommend methods that consider the complete data set and provide a code example. We suggest that the reliability of the tool should be documented not only as internal consistency but also using test-retest measures, ideally combined with interrater agreement. It is desirable that adaptations establish criterion validity against other measures of language development, such as structured tests, spontaneous language samples, or experimental methods. In summary, by critically reviewing the different adaptation strategies, the present review article provides guidance for teams that adapt the MB-CDI into new languages. SUPPLEMENTAL MATERIAL: https://doi.org/10.23641/asha.22661689.