1. PRONUNCIATION
OF THE ENDING
– ED

2. -ED as a Verbal Ending
The ending –ed of the past tense and the past participle of verbs is pronounced:

3. -ED as a Verbal Ending /Id/ after d and t: add - added lift - lifted
end -ended rest - rested
defend - defended wait - waited
pretend - pretended

4. -ED as a Verbal Ending /t/ after voiceless sounds other than t:
/p/ - dropped, shaped, sipped, wrapped
/k/ - dropped, locked, marked, wrecked
/f/ - coughed, laughed, photographed, puffed
/θ/ - bathed, toothed
/s/ - danced, placed, kissed, missed
/∫/ - brushed, flashed, rushed, wished
/t∫/ - pinched, reached, touched, watched

5. -ED as a Verbal Ending /d/ after voiced sounds other than d:
/i: / - keyed, guaranteed
/I/ - pitied, envied, worried, carried
/ɑ:/ - barred, scarred
/ɜ:/ - preferred, referred,
/ə/ answered, bothered, gathered
/eI/- stayed, delayed, played, weighed

6. -ED as a Verbal Ending /d/ after voiced sounds other than d:
/b/ - disturbed, robbed, grabbed
/g/ - begged, dragged
/m/ - aimed, seemed
/ð/ - clothed, bathed, mouthed
/z/ - dazed, pleased, caused
/l/ - called, killed, rolled, boiled, mailed

7. -ED as an Adjectival Ending
the past participles of some verbs are used as adjectives. Then, a second syllable is added even if the base form does not end in a /t/ or /d/ sound, and the "-ed" ending will be pronounced as /id/.

8. -ED as an Adjectival Ending
The following -ed words used as adjectives are pronounced with /Id/:
aged blessed crooked dogged learned naked
ragged wicked wretched

9. -ED as an Adjectival Ending
So we say:
the aged man /Id/
a blessed nuisance /Id/
a dogged persistence /Id/
a learned professor - the professor, who was truly learned /Id/
a wretched beggar - the beggar was wretched /Id/

10. -ED as an Adjectival Ending
But when used as real verbs (past simple and past participle), the normal rules apply and we say:
he aged quickly /d/
he blessed me /t/
they dogged him /d/
he has learned well /d/ or /t/

11. -ED as an Adjectival Ending
The exceptions doesn't apply to teaching pronunciation of English past tense verbs, just past participles when they are used as adjectives.