I used to could do that.
source:
LAGS
Entry:
631
Example:
I used to could do that.
Modal 1:
used to
Modal 2:
could
Gender:
Female
Race/Ethnicity:
White
Age:
77
Level of Education:
5th grade
Home Community, Town, or State:
GA (Columbus)
Location Collected:
GA (Eelbeck)
Year:
1976
Relation to Addressee:
subject to fieldworker
Medium:
Spoken
Sentence Structure:
1.0
Status:
Naturalistic