A shibboleth (/ˈʃɪbəlɛθ/ or /ˈʃɪbələθ/) is a word, sound, or custom that a person unfamiliar with its significance may not pronounce or perform correctly relative to those who are familiar with it.
It is used to identify foreigners or those who do not belong to a particular class or group of people.
It also refers to features of language, and particularly to a word or phrase whose pronunciation identifies a speaker as belonging to a particular group.
This article contains IPA phonetic symbols. Without proper rendering support, you may see question marks, boxes, or other symbols instead of Unicode characters.
"It's weird isn't it: it's like the rhetoric of class warfare has been picked up by the winners of the war, like, the right pretty much won that war, yet they're the ones who can't let go of what they would call the 'tired old shibboleths of class warfare' ..."
Philip then praises him (as he should) for the use of the word :)
In trying to find the word they used here I also found this gem:
Sibilance is a manner of articulation of fricative and affricate consonants, made by directing a stream of air with the tongue towards the sharp edge of the teeth, which are held close together; a consonant that uses sibilance may be called a sibilant. Examples of sibilants are the consonants at the beginning of the English words sip, zip, ship, chip, and Jeep, and the second consonant in vision. The symbols in the International Phonetic Alphabet used to denote the sibilant sounds in these words are, respectively, [s] [z] [ʃ] [tʃ] [dʒ] [ʒ]. (The sounds [tʃ] [dʒ], as in chip and Jeep, are affricates; the rest are fricatives.) Sibilants have a characteristically intense sound, which accounts for their non-linguistic use in getting one's attention (e.g. calling someone using "psst!" or quieting someone using "shhhh!").
In the alveolar hissing sibilants [s] and [z], the back of the tongue forms a narrow channel (is grooved) to focus the stream of air more intensely, resulting in a high pitch. With the hushing sibilants (occasionally termed shibilants), such as English [ʃ], [tʃ], [ʒ], and [dʒ], the tongue is flatter, and the resulting pitch lower.