PRONUNCIATION OF VERBS IN PAST

Pronunciation of -ED

There are basically three ways in English to pronounce the ending -ed of verbs as set out in the past tense. Let's look at each:

Sound [d] voiced (+vibration)

When the verb ends in sound vibration (ie when to pronounce the last letter feel that the sound vibrates in your throat), then, to pronounce the-ed past, it uses sound vibration [d]

listen listened [lísend]
study studied [stádid]
enter entered [énterd]
receive received [risívd]
memorize memorized [mémoraizd]
jam jammed [yámd]
rob robbed [róbd]
clog clogged [clogd]


Sound [t] voiceless (-vibration)
When the verb ends in dull sound (ie when to pronounce the last letter the sound does not vibrate, only thunder in the throat or lips and teeth), then, to pronounce the-ed past, use the dull sound [t]

walk walked [uókt]
talk talked [tókt]
stop stopped [stopt]
jump jumped [yompt]
laugh laughed [laft]
practice practiced [práctist]
match matched [matcht]
watch watched [uátcht]
wash washed [uásht]
close closed [clost]

Sound [êd] ó [id]
When the verb ends in sound [t] or sound [d] (noting that in previous groups none of the verbs ending in these sounds), then, to pronounce the-ed past, it uses sound [ed] whose voice sounds very tight and short.

repeat repeated [ripírêd]
invent invented [invéntêd]
wait waited [uéirêd]
want wanted [uántêd]
decide decided [disáidêd]
add added [ádêd]
include included [inclúdêd]
need needed [nídêd]

Taken to:
http://foro.univision.com/t5/Idioma-Ingl%C3%A9s/Pronunciaci%C3%B3n-de-la-Terminaci%C3%B3n-de-los-Verbos-en-Pasado-en-ED/m-p/64971622