echo "രജീഷ്" | convert -pointsize 48 label:@- image.png gives me nothing but a series of ‘?’ marks of 48 points in the output image.
And convert -font Arial label:'Something' something.png gives me error “convert: unable to read font `Arial'.” instead of a nice image with ‘Something’ in Arial font.
So, what’s the solution? List the fonts available. No, fc-list doesn’t help. You need to use the exact name in the output list of convert -list font to work. There I see Rachana font listed as Rachana-Regular.
And then,
convert -font Rachana-Regular -pointsize 48 label:'രജീഷ്' img_magick.png

Nice!