After careful research, IRS Revenue Ruling 55-431 states if an individual accepts an occasional invitation to make a speech for, which he or she receives an honorarium, he or she is NOT engaged in a trade or business for self-employment tax. In your particular instance, two speaking engagements are occasional and are considered other income.
Here is a link to the journal of Accountancy, which is a trusted source for tax research information. Note the reference it makes to Revenue Ruling 58-112 that characterizes a trade or business activity as one that is regular, frequent and continuous. It also states in the link that Revenue Ruling 55-431 states “as a general rule, an individual who accepts an occasional invitation to make a speech is not engaged in a trade or business.” After this quote, it explains what other income is.
This link briefly references Revenue Ruling 55-431. Please select this hyperlink for more supporting detail.
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