Not just ‘sewi supa’ but ‘lon sewi supa’ “above the plain”
New here? ‘taso’ in sentence first position is probably the oldest and most common use “but”. In this sense it cannot occur inside a sentence, so those uses are “only” (or, possibly, “alone”). I’m not sure that was what was meant. It’s hard to get back into the mood of half a decade ago or os.