*2.1. Participants*

This study included 50 participants (23 female; 27 male) from Managua, Nicaragua. These consisted of 16 Spanish speakers who had typical hearing and no sign language experience (hearing cohort; *Mage* = 29.49, range = 17.0–55.3) and 34 deaf signers of LSN: 10 from the first cohort (*Mage* = 35.51, range = 30.5–50.0), 13 from the second cohort (*Mage* = 25.45, range = 21.5–34.1), and 11 from the third cohort (*Mage* = 20.29, range = 15.9–28.8). All LSN signers had joined the deaf community by the age of six, most upon entering school, and used LSN as their primary daily language since that time. First-cohort signers entered the community between 1974 and 1983; second-cohort signers between 1984 and 1990; third-cohort signers between 1993 and 1999. Ten additional hearing non-signers were tested but were excluded from coding due to errors in video recording. Two additional deaf signers were tested, but their data were excluded due to their history of contact with sign languages other than LSN. One first-cohort signer and four third-cohort signers were unintentionally tested at two different time points. In these cases, we selected the recording that had the best quality video for coding.

All adult participants provided verbal and written consent for participation. Participants under the age of 18 provided verbal and written assent, and their parents provided written consent for their participation. Participants were compensated for their time. Most hearing participants participated in this study only. For all deaf participants and some hearing participants, this study was conducted alongside other studies.
