[Rogozhin]

言う Iu > to say
言った　Itta > said
言ってた Itteta > did say

言う事　Iu koto > what is said（Eg. 言う事をきいてください - Please listen to what is said/what I say)
言った事　Itta koto > what was said （Eg.　なのじょのわるぐちを言った事はない　－　I've never badmouthed her)