Flannel-mouthed

I went to her, sat close beside her and tried snuggling up a little. It worked. . . . "I can get them," I said just as flannel-mouthed as ever I could, like all of us talked to her now.

Source: wiktionary

[N]ot only does Kerry have a flannel-mouthed inability to utter a simple sentence, but his orotundities also serve to reinforce the notion that the Senator from Massachusetts is a patrician stiff, too smug to speak in a manner decipherable by ordinary Americans.

Source: wiktionary