What, if any, are the restrictions concerning transmission of language that may be considered indecent or obscene?

The FCC strictly prohibits the use of indecent or obscene language on the amateur radio bands. Because amateur radio is an open, over-the-air service that anyone—including children—can listen to, operators are legally expected to maintain appropriate standards of communication. There is no specific "list" of banned words maintained by the FCC or the ITU; rather, the rule applies broadly to any language that meets the legal definitions of obscenity or indecency. Operators must always use common sense and good judgment. If a word or phrase could be considered indecent or obscene by the general public, it has no place on amateur radio frequencies.