-ed, -d BrE AmE t, d, ɪd əd —This unstressed ending has three regular pronunciations:
1. After t or d it is pronounced ɪd or, less commonly in British English but regularly in American English, əd , as hated ˈheɪt ɪd AmE ˈheɪt̬ əd, needed ˈniːd ɪd AmE -əd .
(In singing, exceptionally, a strong-vowelled variant ed is usual, as ˈniːd ed .)
2. After the other VOICED consonants or a vowel sound, it is pronounced d , as called kɔːld , seemed siːmd , vowed vaʊd , tied taɪd , feared fɪəd AmE fɪ ə rd .
3. After the other VOICELESS consonants ( p, k, tʃ, f, θ, s, ʃ ), it is pronounced t , as gripped ɡrɪpt , patched pætʃt , knifed naɪft .
Certain adjectives have ɪd, əd against these rules, as wicked ˈwɪk ɪd, -əd . The same applies also to most words in -edly, -edness as markedly ˈmɑːk ɪd li, -əd- AmE ˈmɑːrk əd li . This 'syllabic' pronunciation of the ending formerly applied to all -ed formations, and is still heard when people recite older literature, where it may be required for scansion purposes: thus (only in imitated old pronunciation) seemed ˈsiːm ɪd .