Languages other than English are not supported by kindle format. These have to be read in PDF format on a kindle reader.
I tried to convert .pdf to a Mobi file and uploaded to Kindle. But I was able to read junk in Kindle. May be, the pdf file contains other than the English language (i.e. Kannada, a language spoken in India). Do you have a solution to convert .pdf files having other than the English language to Mobi files to read in Kindle?