Word frequency and distance from the standard language.

<p>Upper left: distance predicted only from longitude and latitude. Upper right: the geographical distribution of random slopes for word frequency. Lower four panels: the combined effect of geography and word frequency on pronunciation distance for the minimum frequency (Q0), the first (Q1) and third quartile (Q3) and the maximum frequency (Q4). Darker shades of gray denote smaller values, lighter shades indicate larger values.