Thorough computer-based Arapaho language lessons are available at CSILW. The lessons below can be used from your mobile. Lots of individual phrase sound files are in the Blog posts on this site too.
Baby, Don’t Cry: Parenting words by Wind River elders with Baby Amelie, backyard recording by Finn Thye, Fall 2012
Arapaho recordings with translations have been archived at University of London with free software called ELAN. Using this is a great way to learn the language; the YouTube description tells how to get software and files.
Basic Arapaho Greetings by Billie Sutton of the Cheyenne Arapaho Language Department
Two hours of Northern Arapaho language lessons from a long long time ago
30 Seconds of spelling with Wayne C’Hair