Susie Gross, a major tprs guru, saw my post on order of acquisition and relayed this telling anecdote. It shows not only the basic fact of a sequence of acquisition, but how teachers fool themselves into thinking their students have “mastered” a grammatical feature.
It was posted to the moretprs listserv:
Thanks for posting this. I met a university ESL department chair back in 1995 or 95 who told about her ESL department’s determination to get students (who were already good in English, extremely intelligent and highly motivated) to acquire the 3rd singular -s. The contortions the instructors went through were amusing, they did it all with ABUNDANT comprehensible input and crazy things to make the students NOTICE the usage.
In the end it did not work, although the students themselves claimed that they always used the 3rd sing -s and that they did not forget it! In the classroom they did begin to use it consistently.
Taped conversations of them speaking when NOT in the classroom (affective filter off) proved that in fact an entire semester of intensive CI with fabulous NOTICING tricks did not pay off. It was not acquired; it was simply used in the classroom when the instructors were present.
It is simply late acquired. Period.