Verbal fluency performance has been widely used as a measure of language proficiency, word retrieval and lexical organization, memory organization, or executive functioning in children and adults in clinical and research settings.
The ability to generate words on the fly has been examined for many spoken languages but it has not been extensively studied in deaf or hearing sign language users with different language backgrounds. How does this ability compare between signed and spoken language? How does the age of exposure to ASL mediate the speed, accuracy, or pattern of sign retrieval?
In one experiment, we examined semantic fluency performance in deaf signers who generated signs in ASL (their dominant language) and compared them with hearing sign-naive monolingual English speakers who produced English words for each of the following categories: 'animals', 'fruits', 'vegetables' and 'clothing'. We found that language, whether spoken or signed, did not influence performance as both signers and speakers retrieved comparable numbers of items, and interestingly, about 30% of the deaf signers' ASL responses were made up of fingerspelling.
In another experiment, we were interested to see if hearing speakers, who are proficient ASL and spoken English, would generate similar numbers of items in both languages. One group of ASL-English bilinguals had deaf parents and used both languages from birth. Another group of ASL-English bilinguals acquired ASL later in adulthood (they were ASL-English interpreters or teachers of the deaf). Semantic fluency scores were higher in English (the dominant language) than ASL (the non-dominant language), regardless of age of ASL acquisition. Again, fingerspelling was relatively common in both groups of signer.
To summarize, modality of the dominant language (spoken or signed) does not affect semantic fluency scores in deaf or hearing adults if fingerspelled forms are considered acceptable responses, and that language dominance rather than age of acquisition affects ASL semantic fluency performance in hearing ASL–English bilinguals
This study showed that verbal fluency tests are generalizable to signed languages. Semantic fluency is sensitive to language dominance and can be used to measure lexical retrieval in both signed and spoken language modalities. Secondly, this study emphasizes the need to consider fingerspelling when assessing semantic fluency in ASL due to the relatively high occurrence of fingerspelling in ASL responses. This is crucial for clinicians and researchers who are relying on these measures as an index of language proficiency, lexical access or executive functioning.
Zed Sevcikova Sehyr, Marcel R Giezen, Karen Emmorey (2018). Comparing Semantic Fluency in American Sign Language and English, The Journal of Deaf Studies and Deaf Education, eny013, https://doi.org/10.1093/deafed/eny013