Mixture has to do with whether the language consists essentially of items and structures derived from no source outside itself.
- Romaine (1988), a pag.44

Mixture over a long period of time involving two or more fully developed languages has results that are different from mixture involving systems which are changing from less complex to more complex. Moreover, natural internal developments and the results of mixing are often indistinguishable.
- Romaine (1988), a pag.67