How do you pronounce "efficacy"?

In American English: /ˈɛfɪˌkæsi/ (EHF-i-kas-ee). In British English: /ˈɛfɪkəsi/ (EHF-ik-uhs-ee). In Canadian English: /ˈɛfɪˌkæsi/ (EHF-i-kas-ee). In Australian English: /ˈɛfɪkəsi/ (EHF-ik-uhs-ee).

Is "efficacy" pronounced differently in American and British English?

Yes. In American English it's pronounced /ˈɛfɪˌkæsi/ (EHF-i-kas-ee), while in British English it's /ˈɛfɪkəsi/ (EHF-ik-uhs-ee).

How to Pronounce "efficacy"

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efficacy

regional

/ˈɛfɪˌkæsi/

EHF-i-kas-ee

Syllable Breakdown

ɛfef·ɪfi·kæsca·icy

Source

80%confidence📘 CMU Pronouncing Dictionary v0.7b

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Last updated: 2026-02-14