AUTHOR=Penn Dustin J. , Számadó Szabolcs TITLE=Commentary: Why Are No Animal Communication Systems Simple Languages? JOURNAL=Frontiers in Psychology VOLUME=12 YEAR=2021 URL=https://www.frontiersin.org/journals/psychology/articles/10.3389/fpsyg.2021.722685 DOI=10.3389/fpsyg.2021.722685 ISSN=1664-1078