Loglan has the advantage that it is grammatically simple to negate any sentence. The issue here is more profound, and Loglan shares the problem, whatever it is, with English. Loglan looks like English in this respect, with one slight difference. Although English has little trouble with simple conjunctions, we can represent sentences in our logic notation with little difficulty which cause English to have fits. Notice the difference in grammatical expression between the inner occurrences of negation and the outermost negation.
Similar considerations apply to negating disjunctions.
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