https://bugzilla.redhat.com/show_bug.cgi?id=1938091
--- Comment #1 from Jens Petersen petersen@redhat.com --- Thanks for reporting this - I am not sure if it is a bug.
Rather personally I find the names of the columns a bit confusing in English: maybe the Japanese is better I dunno.
Non-hiragana "sounds" (input strings) do seem to work. To me output and input would be clearer names for "Spelling" and "Sound" but that might be oversimpling.