but

*der Katze Ohr (The cat's ear).

While control data would make Wode et al.'s argument even more convincing (e.g. ESL with other first languages or English as a first language), their explanation is quite plausible.

Wode et al. also point out that use of cross-sectional techniques, as opposed to longitudinal, fail to make the distinction between true mastery and what Wode et al. call "premature forms". For example, in their data, subjects would first produce forms like "feed", "sheep", and "fish" correctly in the plural, without the /s/ ending. Somewhat later, however, the children would incorrectly add the /s/ marker to these forms, with the correct form re-emerging later. The phenomenon of premature forms is well attested in first language acquisition (Ervin, 1964; Cazden 1972). While Wode et al.'s point is reasonable, the empirical evidence suggests that the existence of agreement between cross-sectional and longitudinal orders is quite high, when sufficient samples are used.

Finally, Wode et al. note that ordering studies might be overly concerned with determining relative order of acquisition of items that are formally quite different. For example, one would not be interested in the relative order of /r/ and negation.

Similarly, Wode et al. suggest that bound and free forms might be "acquisitionally quite different" (p. 184). This is precisely what we have found (Krashen et al., 1978); with bound forms showing very clear consistency across children and adults, L1 and L2, while free forms, which are ordered among themselves with some consistency, appear relatively "later" in L1 acquisition.

Wode et al. conclude that both acquisition order and "developmental sequence" (or "transitional competence") studies "focus on different aspects of the total process of L2 acquisition... therefore, the conclusion cannot be to claim general superiority of one over the other" (p. 184).