Necessary is pronounced NES-ə-ser-ee (IPA /ˈnɛsəˌsɛri/). Stress the first syllable — 'NES-uh-ser-ee'.
IPA: /ˈnɛsəˌsɛri/
Syllables: NES · ə · ser · ee
Common ESL mistake: Learners stress 'ses' saying 'ne-CESS-ary'.
Tip: Stress the first syllable — 'NES-uh-ser-ee'.