She serves as the Josephine Knotts Knowles Professor in Human Biology at Stanford University[1] and has been described as "the leading researcher in infant-directed speech".
[4] She also serves on the advisory board for a California-based company VersaMe which focuses on early childhood education and was partially inspired by Fernald's research.
In the beginning of her study, she found that at the start the children did not seem to have a difference in skills and vocabulary, but at twenty-four months they had an approximate six-month gap.
Her research contributed to the debates during the Civil rights movement, when the question was raised of if there was truly inequalities in education between Black and White schools.
In her research she found that socioeconomic status does affect the way that children develop language, these factors include: childcare and amount of time spent with the child.
Fernald's research contributed to language acquisition and also helped illustrate that there are many factors that go into how a child develops their repertoire in vocabulary.
A main point to be aware of includes the variation between low-income Spanish speaking families and child-directed speech and its predicted effects on vocabulary.
The tests started out by using 80 participants, 20 mothers and 20 fathers of children between 10 and 14 months old and then 20 female and 20 male college students that had no direct experience with infants or kids past the age of 5.
Fernald's tests had 5 natural samples of infant and adult directed speech recorded from mothers of 12-month-old kids in 5 standardized interactional contexts: Attention-bid, Approval, Prohibition, Comfort, and Game/telephone.
They then had the 80 subjects listen to these content filtered speech acts and tried to identify the intent of the speaker by only using the "prosodic" information or the pitch and tone.