Soviti comes from the word sova, which means owl. In my region it is rarely used, and its meaning isn't "to sleep", but to stay up late - similar to vještičariti - which comes from the noun vještica - a witch, and litterally means "to do witchcraft" - both alluding to the fact that both owls and witches do their busyness at night, when normal people sleep.
As for đonjati or džonjati (the latter more frequent in my region), i really have no clue. Nothing even remotely similar comes in mind.