其实翻译是要放在语境里才有实际意义的,拿楼主的问题为例
当表示因为自己说的内容而后悔可译为I regret having said that；
表示说了某些不该告诉听话者的事情译为I regret that I have tell him/her that;
because表示很强烈的语气,只有说话者强调原因的时候才才用because翻译,译为I regreted because I have told it.
say是及物动词,后面应该加宾语.2楼的回答有语法错误.