Alternative: On some firmware versions, the Language option is the very last item on the System page. Scroll all the way down.
Some early versions of the AVN-Z03iW shipped with a locked Japanese ROM that contains only Kanji and Kana characters. If you see an icon for "External Memory" but no "Language" entry, your unit may lack the language files. You need to update the firmware. Visit the Eclipse (now part of Fujitsu Ten/Denso Ten) firmware portal to see if an International ROM is available for your specific hardware revision. eclipse+avnz03iw+change+language
If you are stuck in Japanese, look for these specific characters to find the settings: Menu Button: Look for a physical or touch button labeled メニュー Alternative: On some firmware versions, the Language option
Fast "flick and drag" touch response, similar to a smartphone. If you see an icon for "External Memory"