yes...Not entire North Kerala,only around upper part of kasargod district,bordering Mangalore...Actually it is a part of Tulunadu,But was mistakenly added to Kerala..Even today many in those areas can't speak or even understand basic Malayalam(Though Muslims speaks good Malayalam )...Marathis?? In Northern Kerala!!
Interesting.. Are there no Tulu Christians?
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Tulu Christian-very rare species,some recent converts may be,not sure about Mangalore side...