One of the chief concerns in introductory linguistics programs is introducing students to the great typological diversity of the world's languages. There are a number of different ways in which languages can inflect (or not), structure word order, derive new words from existing vocabulary, etc. Conlangs, however, tend to choose a very limited set of approaches, for example agglutinative inflection is popular because creators feel it makes the language easier to learn. Just as some North American departments have been mocked for doing all their theoretical work purely on the basis of English (or other European languages), using a conlang would make students miss out on the full range of human linguistic expression.

All human languages have at least some irregularities, and the way in which speakers deal with those irregularities is an interesting series of phenomena in itself, but most conlangs aim to be fully regular. A similar situation holds for phonology in which most languages have a developed system of allophony and sandhi, but conlangs typically don't aim to represent those phenomena at all.