Watching this clip of ABC News reporting on the 2DS, I am honestly surprised that I've never heard someone mistakenly refer to the 3DS as 'three-dees.' Sure, it's wrong, but I can kind of see why someone would mispronounce it that way! Same goes for the 2DS.
Observe:
But beyond that, this clip perfectly sums up Nintendo's current naming problem. Not only is the 2DS a tad confusing as a name for a console (I suspect we'll continue to see bumbles like the one in the clip, if not worse), but the Wii U and Wii continue to be confusing for people, too (you catch the anchor referring to the Wii U as the Wii, right?)—this is true even though Nintendo seems to be convinced the name isn't part of the Wii U's problem, sales-wise.
Regardless, good job spotting this, ElectricBlanketFire.
ABC: Nintendo releasing "2 Dees". Plays same games as "3 Dees". Cuts price of "Wii" [neoGAF]