Decoding the letter Z

The letter Z, lowercase z (pronounced /zd/ or /ziː/) very reliably represents the sound /z/. For examples see IPA phoneme /z/.

Exceptionally "z" can have other sounds.
 * azure /ˈæʒər/ - Czech /tʃk/ - Nazi /ˈnɑːtsiː/

"tz"
As /ts/: Antz (movie), chutzpah /ˈhʊtspə/, pretzel /ˈprtsəl/, Pulitzer /ˈpʊlɪtsər/, quartz /kwɔːrts/, Switzerland /ˈswɪtsərlənd/, waltz /wɔːlts, wɔːls/

"zh"
In words form non-Latin alphabets sometimes the sound /ʒ/ is spelled "zh", as in Dr. Zhivago /ʒɪˈvɑːgəʊ/. See IPA phoneme.

"zz"
In Italian loan words "zz" sounds /ts/.
 * mozzarella /ˌmɒtsəˈrlə/, paparazzo /ˌpæpəˈrætsəʊ/, paparazzi /ˌpæpəˈrætsiː/, pizza /ˈpiːtsə/