I don't see why it's important. When listening, if you can hear something at the end, it doesn't matter whether you hear a -d or a -t as long as you recognize it as the past tense. When speaking, I automatically make the right sound. I find it it very difficult to pronounce -t after an unvoiced final sound, "believ't" and just about impossible to pronounce a -d after a voiced final sound, "stopp'd" (without creating an incorrect extra syllable). Is it different for a foreign language learner? In any case, if I do my very best to say "stopp'd" or "believ't" the sounds are so close to the right sound that I don't think a listener would even notice the error. I would ignore the rules, and just try pronouncing the words in a relaxed way, and see what comes out. The only important thing is not to pronounce the "e" vowel and create a syllable at the end (unless you're reading poetry from the 1700s and 1800s!) What do others think?

Put two fingers on your throat and say the following sounds: D T B P V F Z S We could keep going through all the pairs, but you've probably noticed how your throat vibrates only on the first letter of each pair, even though your mouth makes the exact same movement. These are voiced consonants. Don't worry about the rules - just aim to say the words in the easiest and most natural manner. These so-called "rules" are simply a description of how we pronounce these words.

Hey Ali. Are you asking which sounds are voiced and which are unvoiced in English? First, look at this chart: https://en.wikipedia.org/wiki/English_phonology#Consonant_examples The consonants in the column labeled "fortis" are the "unvoiced" ones. The ones in the "lenis" column are "voiced." Now, let's look at some examples. I included some links that have audio you can listen to. You said the rules are the following: 1. If word ends in /t/ or /d/, the -ed sound is /ɪd/ 2. If the ending is unvoiced, the -ed sound is /t/ 3. If voiced, the -ed sound is /d/ 1. nod->nodded = /ˈnɑdɪd/ https://en.wiktionary.org/wiki/nodded 2. stop->stopped = /stɑpt/ https://en.wiktionary.org/wiki/stopped 3. stab->stabbed = /stæbd/ https://en.wiktionary.org/wiki/stabbed 1. "nodded" ends with a "d," so the ending is /ɪd/ in /ˈnɑdɪd/. 2. "stopped" ends in "p," which according to that chart is fortis/unvoiced. So "stopped" has the /t/ ending: /stɑpt/ 3. "stabbed" ends in "b," which is lenis/voiced. So "stabbed" has the /d/ ending: /stæbd/ I recommend you save this chart and use it whenever you aren't sure how to pronounce the -ed endings. Eventually you'll memorize which sounds go together, and you won't need the chart anymore. Good luck!

I suppose unvoiced sounds are more "breathy." Sometimes it helps to put your hand in front of your mouth when you say a sound and if you feel air on your hand, it is unvoiced, but that may not help with all the unvoiced sounds. Another way you could try to remember these rules is to remember which letters/sounds are considered voiced and unvoiced. Here's a breakdown that I've used with students before: 1. Use /t/ after unvoiced final sounds f, k, p, s, (ch), (sh), (th) look - looked (t) push - pushed (t) ask - asked (t) watch - watched (t) help - helped(t) dress - dressed (t) 2. Use /d/ after voiced final sounds b, g, (j), l, m, n, , r, ∂(th), v, z, + vowels sob - sobbed (d) roam - roamed (d) believe - believed (d) judge - judged (d) fill - filled (d) enjoy - enjoyed (d) 3. Use /ed/(another syllable) after final /d/ and /t/ . needed (ed) wait – waited (ed) There may be other approaches, but hopefully that can give you some idea.