As per The Power Still Flows Through Him on pg. 509, a sorcerer can sustain a spell for a number of hours equal to their Forte, minues the spell Obstacle, in hours. If that number is zero or less, you can’t sustain it.
So… does that mean that there’s a minimum Forte requirement to cast any Sustained spells equal to the spell Obs? If so, it would take a Forte of 9 to talk to insects with Low Speech. Am I missing something, or is it just assumed that most of these spells have mimimum duration to “get shit done within a reasonably small amount of time”?
Reading through the thread I was asking myself if a Sustainer Matrix would help, or a trinket with advantage dice for Forte, both done by your friendly enchanter, or yourself beforehand. And I found nothing about the stackability of trinket-based effects (or spells for that matter). Or a charm with the Trait on it, might work with the correct Antecedent(s).
And how about Art Magic? This kind of magic would either help with a kind of Advantage spell or transfering a trait upon the target. In the insect case, Low Speech: Insects or Formorian? Chitterish?
I don’t recall the exact writeup for Matrices, but advantage dice would not help. Notice that the rule Ghola is citing says, in essence, “if Forte-Ob < 1, the spell may not be sustained.” You could, of course, use your advantage dice on Tax tests. But they don’t increase your base Forte, and have no effect on how often you must test while sustaining the spell. (Don’t recalculate Mortal Wound either, for the same reason. This is analogous to the reason Light wounds are worse than Supies.)
EDIT: Conferring a trait, either one which directly affected sustaining spells or one which increased Forte, would work. Conferring advantage would not, as above (though of course it makes the tests easier for spells you can sustain.)
If you’re going to make a new spell, then you might as well just reburn the spell to have a different duration. Make it specifically about insects if that’s all you need, and make it have a very short duration. Those things will both bring down the obstacle too.