the DATEDIFF function in English and its variant in Spanish, do not work; They give error messages, even when you try to test them with the help examples: =FECHADIF("17-04-1974";"13-06-2012";"y") #valor
It depends on the 'Date Acceptance pattern' defined in Tools - Options - Language Settings - Languages. In my case it's D/M/Y;D/M, so this works for me : =DATEDIF("17/04/1974";"13/06/2012";"ym") @Olivier, is it something we should mention in the help page ? -> https://help.libreoffice.org/Calc/DATEDIF
Olivier Hallot committed a patch related to this issue. It has been pushed to "master": http://cgit.freedesktop.org/libreoffice/help/commit/?id=5715a39fdb3eea1b8bd71fc6517c5442bfce1fe5 tdf#119009 Clarify DATEDIF date parsing
In addition to Olivier’s fix above (which can be seen at https://help.libreoffice.org/6.2/en-US/text/scalc/01/func_datedif.html), I’ve updated the Spanish translation to fix the inconsistent translation of the function’s name, which was all over the place: DATEDIF is now called SIFECHA, which is of course wrong (our previous name, FECHADIF, is an accurate translation) but it’s the name used in Excel, and we want to be interoperable, right? (Your existing spreadsheets will continue working under the changed name). Most crucially, the Spanish translation had the arguments wrongly ordered in the examples, and that caused an error when you tried them out in Calc.