An optional string specifying which language's
administrations to retrieve.
form
An optional string specifying which form's administrations to
retrieve.
filter_age
A logical indicating whether to filter the administrations
to ones in the valid age range for their instrument
mode
A string indicating connection mode: one of "local",
or "remote" (defaults to "remote")
Value
A data frame where each row is a CDI administration and each column
is a variable about the administration (data_id, age,
comprehension, production), its instrument (language,
form), or its child (birth_order, ethnicity,
sex, mom_ed).