More than any other field, my understanding of language improves when I learn a new taxonomy.
Langue is a language defined by a grammar, than someone smart wrote down on a book and the community generally agrees with it. In Chomskian terms, it roughly corresponds to linguistic competence. The list of words and the list of rules defines the language. The langue exists even if all the speakers are dead.
Parole is the language as it is used. In Chomskian terms, it corresponds to linguistic performance. The corpus, the way people speak, including speech “errors,” awkward phrasings and so on define the parole.
A valid sentence in a langue, may be so deeply recursively nested that it it is never attested. Corpus linguistics, keeps turning up sentences that don’t fit the over all pattern of the langue, leading to more and more rules and variations on the rules.
Con-langues are common– most conlangers start with a word list and a bunch of rules. Con-paroles are rare. First off, it takes years to learn a language poorly, decades to learn it well.
Con-paroles (conlangs with 2 or more competent users, and/or a sizable corpus)
- toki pona
- Lojban (?) People do chat in Lojban, but there is some question about how big the gap between langue and parole is.
… list to be continued…