Lexical comparisons of signed languages present new methodological challenges not found in comparisons of spoken languages. Two standards for comparing wordlists are examined using a sample of four European sign languages that are not known to be related to each other and a second sample of different dialects of the signed languages of Spain. The use of different standards is shown to affect the numerical results; comparing signs on the basis of probable historical relatedness typically yields percentages that are 5-10% greater than comparisons on the basis of similarity. The amount of iconicity inherent in signed languages affects the wordlist scores even more. Comparing lexical items that were chosen for their low potential for iconicity resulted in significantly lower scores among unrelated languages than did word lists of basic vocabulary or highly iconic signs. Conversely, the non-iconic word list comparison showed greater similarity between closely related language varieties. Therefore, wordlists that are low in iconicity give more insightful results than wordlists that include significant numbers of iconic items.
Parkhurst, Stephen J. and Parkhurst, Dianne
"Lexical comparisons of signed languages and the effects of iconicity,"
Work Papers of the Summer Institute of Linguistics, University of North Dakota Session: Vol. 47, Article 2.
Available at: https://commons.und.edu/sil-work-papers/vol47/iss1/2