  As one of the Web's primary multilingual knowledge sources, Wikipedia is read
by millions of people across the globe every day. Despite this global
readership, little is known about why users read Wikipedia's various language
editions. To bridge this gap, we conduct a comparative study by combining a
large-scale survey of Wikipedia readers across 14 language editions with a
log-based analysis of user activity. We proceed in three steps. First, we
analyze the survey results to compare the prevalence of Wikipedia use cases
across languages, discovering commonalities, but also substantial differences,
among Wikipedia languages with respect to their usage. Second, we match survey
responses to the respondents' traces in Wikipedia's server logs to characterize
behavioral patterns associated with specific use cases, finding that
distinctive patterns consistently mark certain use cases across language
editions. Third, we show that certain Wikipedia use cases are more common in
countries with certain socio-economic characteristics; e.g., in-depth reading
of Wikipedia articles is substantially more common in countries with a low
Human Development Index. These findings advance our understanding of reader
motivations and behaviors across Wikipedia languages and have implications for
Wikipedia editors and developers of Wikipedia and other Web technologies.
