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 precisely to operationalise morality in a five-dimensional scale system. Recent developments of the theory urged for the introduction of a new foundation, liberty. Being only recently added to the theory, there are no available linguistic resources to assess liberty from text corpora. Given its importance to current social issues such as the vaccination debate, we propose a data-driven approach to derive a liberty lexicon based on aligned documents from online encyclopedias with different worldviews. Despite the preliminary nature of our study, we show proof of the concept that large encyclopedia corpora can point out differences in the way people with contrasting viewpoints express themselves. Such differences can be used to derive a novel lexicon, identifying linguistic markers of the liberty foundation.