You have to use Fable or Opus 4.6 for tolerable language output.
Using Opus 4.7-5 is harmful to your health.
Using Opus 4.7-5 is harmful to your health.
But lately I haven't downgraded because 5 is so much better at tool use, so I just accept the cost of Fable for chatting and hope Opus 5.1 fixes this mess.