(Note: This interview first aired last year.) As more people today identify as non-binary, individuals often introduce themselves by the pronouns with which they identify. E-mails are, for example, sometimes signed with "he/him/his," "she/her/hers," or "they/them/theirs." Pronouns are now playing a prominent role in our gender politics. This may seem new, but linguists have been puzzling over pronouns for a century -- or longer. Conflicts over pronoun usage in this country go back at least to the days of women's suffrage and gender equality, and by now it's common to see "they" (a word long thought to be only plural) being used to denote a gender-neutral singular person. Our guest on ST began the research for his latest book while exploring the varied history of alternatives to "they." Dennis Baron, a professor emeritus of English and linguistics at the University of Illinois, is our guest; his book is "What's Your Pronoun? Beyond He & She."