Joshua Dyal said:

Since Planescape isn't a 3e/3.5 setting, I imagine not. Unless you're referring to some other cant.

In earlier editions (1e, anyway), "thieves' cant" was a special language that (IIRC) could only be learned by members of the thief class, much like Druidic and Druids. Its primary purpose was to let members of the thieves' guild talk about robberies without sounding like they were talking about robberies.

As has been noted, this was replaced with Innuendo in 3.0, and folded into Bluff in 3.5.

Still, if one wanted the old-style Thieves' Cant, it's trivial to just add it to the language list.

J

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