The CATIE Center has created a prototype Digital Learning Repository. On their site, you can find videos in ASL, Spanish, and English for trilingual interpreting practice. Here is a link to a refined search of their repository for ASL, Spanish, and English practice resources for Trilingual Interpreters.
To support clarity in understanding the role of Translators, Interpreters, Transcriber-Translators and Terminologists, our associations endorse various definitions. Please see the attached document below, which was endorsed by Association internationale des interprètes de conférence (AIIC), Mano a Mano, National Association of Judiciary Interpreters and Translators (NAJIT), National Council on Interpreting in Health Care (NCIHC), and Oregon Society of Translators and Interpreters (OSTI)
http://www.interpretereducation.org/specialization/aslspanishenglish/ then click the ASL/Spanish/English Resources tab. On that page you will also find Toward Effective Practice: Interpreting in Spanish-Influenced Settings and Hacia Las Prácticas Efectivas: Interpretación en Situaciones Influenciadas por el Español