Decision is pronounced də-SIZH-ən (IPA /dɪˈsɪʒən/). Stress 'SIZH'; the 'si' becomes 'zh' like in 'vision'.
IPA: /dɪˈsɪʒən/
Syllables: də · SIZH · ən
Common ESL mistake: Learners say 'de-SIS-yun' with /s/ instead of /ʒ/.
Tip: Stress 'SIZH'; the 'si' becomes 'zh' like in 'vision'.