I found this question, Is there a fix for the "Too many open files in system" error on OS X 10.7.1? , and specifically this answer
and the output from that command was:
562 com.apple 580 firefox 716 eclipse 825 Microsoft 874 Google 950 plugin-co 953 plugin-co 1901 AppleSpel 2563 AppleSpel 2646 AppleSpel
WTF? Why does Spell waste all open files? I use it very, I think, averagely. A few documents in Pages, Safari and Messages. This is El Capitan 10.11.
How do I prevent the spelling service to grind my system to a halt?