Background <p>Although the efficacy of cognitive behavioral therapy (CBT) for children and adolescents with anxiety disorders has been supported, empirical data focusing on culturally specific verbal expressions between therapists and clients within CBT sessions across different countries is scarce. This study examined <i>verbalization</i>, cultural expressions of emotional states, across CBT treatment delivered in Australia and Japan.</p> Methods <p>Our sample included a total of 60 children: 30 from Australia (aged 7–15 years) and 30 from Japan (aged 8–15 years). Using video files and written transcriptions of CBT sessions, negative emotional words including both anxiety and non-anxiety words, positive emotional words, and onomatopoeia expressed from children and their therapists were extracted.</p> Results <p>Therapists in Australia used anxiety words more frequently, whereas those in Japan used more non-anxiety words than anxiety words. Although the frequency of negative emotional words in total was not significantly different between two countries, Japanese children expressed more non-anxiety-specific words. Moreover, the use of positive emotional words by therapists correlated with remission of anxiety diagnoses in both countries, whereas occurrence of negative emotional words by Japanese therapists and positive emotional words by Australian children predicted to be free from primary anxiety disorders. Although onomatopoeia was only found within Japanese CBT sessions, the frequency did not predict any treatment outcomes. Finally, network analyses indicated that network structures of negative and positive emotional words from children and therapists show different patterns between the two countries and that such patterns change through CBT sessions.</p> Conclusions <p>This study provides insights into how often emotional words are observed during CBT sessions in Japan and Australia and how these factors predict treatment outcome.</p>