As regulars Fred Armisen and Bobby Moynihan impersonated New York Mayor Michael Bloomberg and New Jersey Governor Chris Christie in the press conference sketch about the Hurricane Sandy disaster, two castmates offered comic signing beside them.
But Matlin wasn't laughing - she found the skit offensive and took to Twitter.com to slam the show's producers and the stars themselves.
In a series of angry tweets, she wrote, "Millions of deaf people use sign (language). Why poke fun/fake it? Poke fun at ME but not the language.
"Sign is not mime; it is a legit language. That's why I developed an App #MarleeSigns to teach it. As I've said, I don't mind fun poked at me, as I poke back. But at the language, that millions use? It feels childish and insulting.
"Here's my point. Deaf people HAVE a sense of humor... But faking signs that we use isn't the same. Imagine if a show started making fun of Spanish (using fake Spanish) or Japanese. Do you think they'd actually get away with it? Uh, no...
"The jokes about sign cold (sic) be funny if done right... Seinfeld, Family Guy, My Name is Earl WERE funny. This stuff is just dumb."