em- BrE AmE ɪm, (¦ )em —This prefix is stressed ¦em if the following syllable is unstressed ( ˌ embro ˈ cation). Otherwise it is unstressed (em ˈ balm) . When it is unstressed, a weak-vowel form ɪm is preferred in Received Pronunciation, although some speakers, particularly regional ones, use a strong-vowel form em .
EM-
Meaning of EM- in English
Longman Pronunciation English Dictionary. Английский словарь произношений Longman. 2012