  Quantifying the moral narratives expressed in the user-generated text, news,
or public discourses is fundamental for understanding individuals' concerns and
viewpoints and preventing violent protests and social polarisation. The Moral
Foundation Theory (MFT) was developed to operationalise morality in a
five-dimensional scale system. Recent developments of the theory urged for the
introduction of a new foundation, the Liberty Foundation. Being only recently
added to the theory, there are no available linguistic resources to assess
whether liberty is present in text corpora. Given its importance to current
social issues such as the vaccination debate, we propose two data-driven
approaches, deriving two candidate lexicons generated based on aligned
documents from online news sources with different worldviews. After extensive
experimentation, we contribute to the research community a novel lexicon that
assesses the liberty moral foundation in the way individuals with contrasting
viewpoints express themselves through written text. The LibertyMFD dictionary
can be a valuable tool for policymakers to understand diverse viewpoints on
controversial social issues such as vaccination, abortion, or even uprisings,
as they happen and on a large scale.
