Are there any languages that distinguish fewer modal categories in the negative than they do in the affirmative?
I can think of one example of a language, Burmese, that appears to show fewer tense-aspect distinctions in the negative than in the affirmative, but I'm curious whether there are any examples of a similar phenomenon for mood.
According to this chapter on symmetric and assymetric negation, Burmese has a negative particle that partially occupies the slot taken by a tense-aspect particle.
I can't tell based on the article or the original dissertation whether the morpheme bí (glossed as PERF) is perfective or perfect.
θwâ-dé go-ACTUAL ((s)he) goes/went. θwâ-mé go-POTENTIAL ((s)he) will go. θwâ-bí go-PERF ((s)he) has gone. ma-θwâ-bû NEGATIVE-go-NEGATIVE ((s)he) does/did/will not go, has not gone
The original source of the examples is this dissertation.
The dissertation is available on Wikimedia commons here.
Here is the PDF and the data is on page 13 by internal numbering (15 by PDF numbering).