As far as I can see, Walloon is not a French dialect.
Walloon much much more different from French than
American English is to English Enlish,
and Austrian German is to German German.
From my reading Waloon is as different from French as Danish is to German or Dutch.
You can look at some translations for some computer programs at:
I think it would be unfair to Wallon to delay the acceptance of the 2-letter code.
I also think it is inconsistent to allow a 3-letter code and then say that it is
not really a language, but a dialect. ISO 639-2 is not used for dialects.
ISO 639-1 code should be reserved for major languages, and there I think
it has been documented that Wallon qualify.