Here is how the words should be sorted this week (note the vertical columns this week):
Silent t
castle
whistle
fasten
listen
often
soften
(wrestle) - this could also go in silent w
silent g
design
resign
assignment
Silent W
wrinkle
wreckage
wrestle
answer
Silent k
knuckle
knowledge
Silent h
honest
honor
rhyme
rhythm
Silent gh
through
thought
brought
bought
though