Simplify the following text for a Grade 3 native English-speaking person.
Original: The strongest such Central Pacific El NiÃ o event known occurred in 2009-2010 . Extreme weather conditions related with the El NiÃ o cycle are associated with changes in the incidence of epidemic diseases .
Simplified: It is also called El NiÃ o and La NiÃ a. El Nino and La Nina are English words for the Spanish words El NiÃ o and La NiÃ a. In Spanish they mean the `` little boy '' and the `` little girl '' .