I don’t see Hawaiian in the list of source languages nor can it be found by searching the list of source languages. However, Hawaiian can be auto-detected. For example, translate “kohola”: The source language is “Detected (haw)”, and the text is translated correctly.
The user should be able to specify Hawaiian as the source language. There are cases where auto-detect doesn’t detect the language is Hawaiian. E.g. “wai”
iPhone iOS 18.3.1, Safari