  Misinformation and disinformation are growing threats in the digital age,
spreading rapidly across languages and borders. This paper investigates the
prevalence and dynamics of multilingual misinformation through an analysis of
over 250,000 unique fact-checks spanning 95 languages. First, we find that
while the majority of misinformation claims are only fact-checked once, 11.7%,
corresponding to more than 21,000 claims, are checked multiple times. Using
fact-checks as a proxy for the spread of misinformation, we find 33% of
repeated claims cross linguistic boundaries, suggesting that some
misinformation permeates language barriers. However, spreading patterns exhibit
strong homophily, with misinformation more likely to spread within the same
language. To study the evolution of claims over time and mutations across
languages, we represent fact-checks with multilingual sentence embeddings and
cluster semantically similar claims. We analyze the connected components and
shortest paths connecting different versions of a claim finding that claims
gradually drift over time and undergo greater alteration when traversing
languages. Overall, this novel investigation of multilingual misinformation
provides key insights. It quantifies redundant fact-checking efforts,
establishes that some claims diffuse across languages, measures linguistic
homophily, and models the temporal and cross-lingual evolution of claims. The
findings advocate for expanded information sharing between fact-checkers
globally while underscoring the importance of localized verification.
