I am happy to answer any questions via email (<jschwab@uos.de>) or OSF comments.
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Historically, the development and decline of polarity-sensitivity has
been observed for NPIs in various languages. Still, the processes via
which such language changes occur are poorly understood. In this study,
we present comprehension and production data that questions whether the
German NPI 'sonderlich' ('particularly') is losing its
polarity-sensitivity. Participants rated affirmative (ungrammatical)
sentences with the NPI as more natural and produced them to greater
extents than negative sentences. The results clash with corpus data on
the distribution of 'sonderlich' and with experimental findings for
other NPIs. We thus argue that our participants were not processing
'sonderlich' as polarity-sensitive item.