Support for baby signing (BS) with hearing infants tends to converge toward three camps or positions. Those who advocate BS to advance infant language, literacy, behavioral, and cognitive development rely heavily on anecdotal evidence and social media to support their claims. Those who advocate BS as an introduction to another language, such as American Sign Language (ASL), advocate early bilingual language learning. A third group warns against BS, emphasizing that it competes for attention with, and thereby potentially delays, spoken language acquisition in hearing infants. Empirical evidence to support any of these camps has been scarce.
In this retrospective investigation we analyzed videotapes of sixteen infants from 9 through 18 months of age; eight had been exposed to BS, and eight had not been exposed to signing (NS). We compared their manual activity and found no differences in the quantity of manual activity accompanying vocal activity and no qualitative differences in the handshapes used during manual and vocal activity. More babies in the BS group reached the 4-, 10-, and 25-word milestones than babies in the NS group, but the differences were not statistically significant. In addition, monthly lexical growth from 12 to 18 months did not reveal signing to have a statistical impact on vocabulary acquisition.
Discussion of these findings points to a tight relationship between manual and vocal activity in all sixteen babies, a relationship that aligns with previous theories and research on gestural and vocal development. Failure to find a statistical difference between the two groups’ development of words, however, calls for temperance in claiming that baby signing facilitates early word learning and cautions against claims that baby signing interferes with word learning.