  The words we use to talk about the current epidemiological crisis on social
media can inform us on how we are conceptualizing the pandemic and how we are
reacting to its development. This paper provides an extensive explorative
analysis of how the discourse about Covid-19 reported on Twitter changes
through time, focusing on the first wave of this pandemic. Based on an
extensive corpus of tweets (produced between 20th March and 1st July 2020)
first we show how the topics associated with the development of the pandemic
changed through time, using topic modeling. Second, we show how the sentiment
polarity of the language used in the tweets changed from a relatively positive
valence during the first lockdown, toward a more negative valence in
correspondence with the reopening. Third we show how the average subjectivity
of the tweets increased linearly and fourth, how the popular and frequently
used figurative frame of WAR changed when real riots and fights entered the
discourse.
