Special pronunciation of -ed

How is the end sound of -ed pronounced in English? 

The suffix -ed has three different pronunciations in English /d/  /t/ and /id/

In my years of teaching English to speakers of other languages, this has been a frequent pronunciation problem and that is understandable - 2 letters pronounced 3 ways and the past tense of most verbs in English are created with these 2 letters - ed.

So how do you know which words say /d/ which say /t/ and which say /id/?  Can you place the words above in the correct column for end sound?

The reality is that most native speakers cannot tell you any rule.  They grew up saying the words correctly because they "absorbed" the language rather than studying and learning it.  So how do you know?

The simple way is to remember ONLY words that already contain d or t before -ed say /id/.    So if the word ends in -ded or -ted then and only then does it say /id/.  The other words ending in -ed will say /d/ or /t/.

It will be very difficult for you to say a word that should be said with a /d/ end sound with a /t/ end sound so this one rule should help you.  Try saying called with a /t/ sound insteand of the /d/ as it is properly said.  It is next to impossible.  you could say call /id/ but that we know is wrong but saying call/t/?  I can't.

For those wanting a rule for /t/ you can memorize:  words that end -s, -sh, c, -ch, x, k, p, f, gh will all end with a /t/ sound.   So placed = plac/t/; ask = as/t/ guess = guess/t/  and so forth.  Watched is one that Chinese loved to say watch/id/ so remember it isn't /id/ but /t/.

I hope that helps.