The media frequently describes the 2017 Charlottesville ‘Unite the Right’ rally as a turning point for the alt-right and white supremacist movements. Social movement theory suggests that the media attention and public discourse concerning the rally may have influenced the alt-right, but this has yet to be empirically tested. The current study investigates whether there are differences in language use between 7,142 alt-right and progressive YouTube channels, in addition to measuring possible changes as a result of the rally. To do so, we create structural topic models and measure bigram proportions in video transcripts, spanning eight weeks before to eight weeks after the rally. We observe differences in topics between the two groups, with the ‘alternative influencers’ for example discussing topics related to race and free speech to an increasing and larger extent than progressive channels. We also observe structural breakpoints in the use of bigrams at the time of the rally, suggesting there are changes in language use within the two groups as a result of the rally. While most changes relate to mentions of the rally itself, the alternative group also shows an increase in promotion of their YouTube channels. Results are discussed in light of social movement theory, followed by a discussion of potential implications for the understanding of the alt-right and their language use on YouTube. **File information** Data: - 'k40.Rdata' contains the structural topic model for unigrams, with 40 topics. - 'k50_bigrams.Rdata' contains the structural topic model for bigrams, with 50 topics. - Dataframes with bigram proportions are in 'p_bi_long.Rdata' (progressive group) and 'a_bi_long.Rdata' (alternative group) Additional plots: - Unigrams_kplot is a plot of semantic coherence vs. term exclusivity for the unigram structural topic model - Bigrams_kplot is a plot of semantic coherence vs. term exclusivity for the bigram structural topic model