CREATE TABLE table_14071 ("Gothic Letter" TEXT, "Roman" TEXT, "Sound  ( phoneme ) " TEXT, "Sound  ( allophone ) " TEXT, "Proto-Germanic origin" TEXT)

Which Gothic Letter has Proto-Germanic origin of / /; /b/?
SELECT "Gothic Letter" FROM table_14071 WHERE "Proto-Germanic origin" = '/ɸ/; /b/'
SELECT "Gothic Letter" FROM "table_14071" WHERE "Proto-Germanic origin" = '/ɸ/; /b/'