This applied study assesses the degree to which speakers re-use and acknowledge parts of one another’s utterances. This form of alignment is called resonance (DuBois 2014; Tantucci and Wang 2021), and is a decisive indicator of creativity and verbal engagement. Consistent absence of resonance indicates interactional detachment, which is distinctive of autistic speech (Tantucci and Wang 2023). We analysed resonance in naturalistic interaction among British speakers in the demographically sampled sections of the British National Corpora of English: the BNC1994 and the BNC2014. We controlled for creativity, age, class, gender, context, dialect, and intra-generational speech for 1,600 turns of informal speech. We discovered that upper-class people from the corporate world and neighbouring sectors mutually resonated much more in 2014 than they used to in 1994. This may be due to the dramatic change in corporate and institutional communication in the 2000s, involving a new turn towards corporate social responsibility, participatory frameworks in higher education, and the enactment of ideologies such as inclusivity, engagement, and equality in higher social grades of British society. This plausibly affected not only the system of values of those communities but also their interactional behaviour, now increasingly geared towards overt acknowledgement of other people’s talk.