'slowly-handled' originates from the combination of 'slowly' and 'handled', where 'slowly' means 'at a slow pace' and 'handled' means 'managed or dealt with'.

'Slowly' and 'handled' have been used separately in English for centuries, and their combination into 'slowly-handled' is a modern construct to describe a specific manner of handling.

Initially, 'slowly' and 'handled' were used separately, but their combination now specifically describes the manner of handling.