On the one hand are errors that involve some kinds of misordering, sometimes called "syntagmatic" or "contextual errors". In this category are exchanges, anticipations, perseverations, shifts, anticipatory and perseveratory additions, and some kinds of deletions.
- Dell (2004), a pag.126

Within the context of the theory one can expect errors of two distinct types occurring at each level of representation - misordering or contextual errors, in which intruding item or items come from the intended utterance, and noncontextual errors, in which the interference comes from outside of the utterance. [...] misorderings include anticipations, perseverations, exchanges, shifts, and some types of deletion and addition errors.
- Dell (2004), a pag.141