Letter Yy and Zz

Yo Yo – [yoh-yoh] – /ˈyoʊ yoʊ/
Yell – [yel] – /yɛl/

Zebra – [zee-bruh; British also zeb-ruh] – /ˈzi brə; British also ˈzɛb rə/
Zipper – [zip-er] – /ˈzɪp ər/