"According to the Watchtower, the Catholic Church is a huge part of Babylon the Great which is led by Satan and his demons. Raymundus Martini, a Catholic Monk (who "represents" Babylon the Great to some extent), woke up one day in the 13th Century and decided to alter YHWH so it can be easily pronounced. Hence the SPANISH-ish version of YHWH was created... Jehova... (sounds something like this in Spanish: Heh-O-Va)"
Apparently, the alteration goes back even further.