Fig. 1: Therapist speech phase-dependence.

The dynamic nature of therapist speech, grouped by language feature category. It represents trends in therapist language over time after aggregating across therapists. LIWC = Linguistic Inquiry and Word Count, a dictionary-based lexicon that maps words and word stems to psychologically relevant categories. EmoLex = Word-Emotion Association Lexicon, a list of English words mapped to crowdsourced sentiment annotations. We performed smoothing/interpolation between discrete points at the level of temporal quintiles using a natural cubic spline. See Fig. 2 for per-feature examples of these trends viewed without smoothing.