Went letter by letter, to Brits

SPELT

Think of how Americans might say "spelled" if they were using British vocabulary.

In British English, "spelt" is the past tense of "spell," meaning to go through something letter by letter. The clue plays on this by hinting at the action ("went letter by letter") while nodding to British usage with "to Brits." It’s a straightforward definition with a slight cultural twist, since Americans would typically say "spelled."