Sounds like the person whose name it was also gave up trying to use Cymraeg, otherwise they'd perhaps be CluEllen. Don't know how long off the boat they were,

Sounds like the person whose name it was also gave up trying to use Cymraeg, otherwise they'd perhaps be CluEllen. Don't know how long off the boat they were, but often misspellings in UK surnames arise across generations in records. I guess because the family themselves are totally illiterate. Also, IIUC on immigration to USA officials would record your surname on your papers and that became _the_ spelling, so that might also explain it?