Platdeutsch or Plattdeutsch: How To spell?
The word Platdeutsch is misspelled against Plattdeutsch, a noun meaning "The modern dialects spoken in the north of Germany, taken collectively; modern Low German. See Low German, under German."
Plattdeutsch has double "tt" is mispronounced as "t"Remember double 'TT' in between the strings pla & deutsch which should not be misspelled with single 'T'
Wrong Spelling:  pla-t-deutsch  Correct Spelling:  pla-tt-deutsch 
Check more misspelled words of Plattdeutsch to spell it correct.