The new and slightly better version of this script (v3) can be found here: https://sites.google.com/view/uhm-o-meter. This version includes an option to count filled pauses (uhm's). The algorithm and validation can be found here:
De Jong, N.H., Pacilly, J., & Heeren, W. (2021). PRAAT scripts to measure speed fluency and breakdown fluency in speech automatically, Assessment in Education: Principles, Policy & Practice, 28:4, 456-476, DOI: 10.1080/0969594X.2021.1951162