"-ate" and the long "a"?

[BobK]

another question: words ending with "-ication"
`
Can I pronounce them as "-/aɪkeɪʃən/" instead of "-/ɪkeɪʃən"?
`
...

No.

Modification = [mɔdəfəkeʃən] ([mOd@f@keS@n])

No, you certainly can't dihen. But stick to your (second) transcription, for British English.

b