  Languages are continuously undergoing changes, and the mechanisms that
underlie these changes are still a matter of debate. In this work, we approach
language evolution through the lens of causality in order to model not only how
various distributional factors associate with language change, but how they
causally affect it. In particular, we study slang, which is an informal
language that is typically restricted to a specific group or social setting. We
analyze the semantic change and frequency shift of slang words and compare them
to those of standard, nonslang words. With causal discovery and causal
inference techniques, we measure the effect that word type (slang/nonslang) has
on both semantic change and frequency shift, as well as its relationship to
frequency, polysemy and part of speech. Our analysis provides some new insights
in the study of language change, e.g., we show that slang words undergo less
semantic change but tend to have larger frequency shifts over time.
