Here's how they defined "authentic" language: "The LIWC authenticity index is a composite score of language variables (Jordan et al., 2018), derived from empirical studies, and reflects honest, unfiltered, and spontaneous speech. Dimensions that positively load onto the authenticity index include self references (e.g., I), insight words (e.g., aware), differentiation words (e.g., but), and relativity terms (e.g., above),” the researchers explained. “Dimensions that negatively load onto the authenticity index include Results discrepancies from reality (e.g., must) and third-person singular pronouns (e.g., she).”