Hi, @MMater , thanks for the question!
On first glance, that sounds like self-employment income. The only possible exception I can think of is that you might be able to claim it's a "sporadic activity". I think the main question here is: did you and do you seek out these speaking engagements, and/or indicate availability for them? If so, then this likely would be considered self-employment income by the IRS.
Hope this helps, please let me know if not!
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