Pluralisation of Latin Words [duplicate]

Solution 1:

With its Latin origins, 'referendum' has both 'referenda' and 'referendums' as its plurals, though dictionaries diverge over which to present as the primary form.

Yet note that 'stadiums' and 'stadia' express different meanings: the former is 'sports grounds' while the latter is 'stages of a disease'.

The discourse on the word 'data' is more complex, concerning some other considerations that you can find here (http://english.stackexchange.com/questions/81707/data-is-are-in-a-global-context) and here (http://english.stackexchange.com/questions/6904/is-data-considered-singular-or-plural).