**5. Conclusions**

Investigating Handling–Object handshape contrasts and conventionalization in homesigners, hearing communication partners, and hearing non-signing adults has offered some insight into how this type of patterned iconicity develops. While there was a grea<sup>t</sup> deal of variation in handshape type preference, overall, gesturers tended to use more Handling forms. Age was the most influential participant characteristic, as the age of the homesigner and communication partner as well as the communication partners' years of experience using the homesign system were significant factors related to conventionalization. Although proxy measures of lexical frequency did not appear to be related to the degree of conventionalization, the instrument type did seem to make a difference to conventionalization. While families with adult homesigners were more conventionalized compared to families with child/adolescent homesigners, they still did not achieve anything close to full conventionalization. Compared to the trajectories in emerging sign languages, these handshape preferences and conventionalization do not seem to reliably appear within two to three decades of use in a family unit consisting of a single homesigner among hearing family members, when only the one deaf person uses the system as a primary system. Looking at the transition from homesign to Nicaraguan Sign Language will also shed light on the role of community participation in the development of iconic handshape preferences. Future research should aim to investigate how individual biases, item-specific biases, and shared/limited usage of a communication system influence these outcomes, both at the level of handshape class and at the level of specific handshape.

**Supplementary Materials:** The following supporting information are available online at https: //www.mdpi.com/article/10.3390/languages7030156/s1, Video S1a: Handling [mop]; Video S1b: Object [handsaw]; Video S1c: Handling+Object [rake]; Video H+O-SIM [mascara].

**Author Contributions:** Conceptualization, D.B. and M.C.; methodology, D.B. and M.C.; formal analysis, M.Q.; investigation, M.C.; resources, M.C and D.B.; writing—original draft preparation, M.Q.; writing—review and editing, M.Q., D.B. and M.C.; visualization, M.Q.; supervision, D.B. and M.C.; funding acquisition, D.B. and M.C. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by NSF BCS-0547554 and BCS-1227908 (to D.B. and S. Goldin-Meadow) and by NIH P30 DC010751 (to M.C. and D. Lillo-Martin).

**Institutional Review Board Statement:** The study was conducted according to the guidelines of the Declaration of Helsinki, and approved by the Institutional Review Board (or Ethics Committee) of Purdue University (PURD0603003706 02/23/2011).

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study.

**Data Availability Statement:** Datasets from this project are available on OSF at the following link: https://osf.io/db7yk/?view\_only=1cf74efc936f45828abfc52fb22c3f9a.

**Acknowledgments:** We thank all of the homesigners, their friends and family members, and the hearing adults in Nicaragua for allowing us to learn from them. We are grateful to the directors and staff of the Center for Special Education in Estelí for their support of this project. Julia Adell, Emily Carrigan, and Deanna Gagne assisted with data collection, and Claudia Molina and Leybi Tinoco graciously provided data collection support in the field in Nicaragua. Tiffani Brophy and Julia Adell coded the video recordings. We also thank Laura Horton for providing feedback on prior drafts.

**Conflicts of Interest:** The authors declare no conflict of interest.
