In casual American conversation, "latter" and "ladder" sound nearly identical in most regional accents. "Letter" should be quite distinct, however, with the "ehh" (Edward) vowel sound instead of the "ahh" (apple) in latter/ladder.

I am not sure about latter,but letter and ladder are with different pronunciation.While the double T in letter is pronounced like a normal T(like in tire),the double D are more like D(like in diagram). I hope i helped :)

I pronounce them the same :) (NE USA)

latter and ladder are both pronounced "lædə" in American, however, the /d/ in latter sounds more slippery because it is a liquid /d/, which is a sound between /d/ and /l/. This is very common in some Chinese dialects, we call this "流音化". When we say this kind of /d/ , madarin speakers would think we just said /l/.

Thanks guys. I maneged to hear the difference between them. :)