Acquiring Language as a Twin

Event start date
Event start time
12.00
Place

Linna building, Väinö Linna auditorium, address: Kalevantie 5.

Doctoral defence of M.Sc. Hanna Elo

Acquiring Language as a Twin : Twin children´s early health, social environment and emerging language skills

The field of science of the dissertation is Logopedics.

The opponent is Associate professor Melanie Soderstrom (University of Manitoba, Canada). Professor Anna-Maija Korpijaakko-Huuhka acts as the custos.

The language of the dissertation defence is English.

Acquiring Language as a Twin

Typically, children learn to master the language they are exposed to in everyday interactions, but twin children are at risk for delayed language development. The onset of the delay is, however, not known, and there is no consensus about the etiology of the delay. Some studies have emphasized the role of pre- and perinatal health factors, while others underline the role of social environment and specifically the everyday interaction occurring in family homes.

Previous studies on twin family interaction have relied on small, qualitative, and non-representative samples. Therefore, in this study, a novel automated method (LENA™) was assessed, and its analyses were utilized to quantify the interaction occurring in family homes. In addition to method testing, the current study was aimed at describing the early language development of twins and studying the effects of the biomedical and social environment on twins’ early language development. The developmental information of twins’ language acquisition was gathered via parent reports on the onset of vocal milestones and the emergence of first words. In addition, parents reported on the development of their children’s vocabularies and other language skills at the age of 12, 18, and 24 months.

The automated method showed to be reliable in detecting the speech of children and female adults, but reliable to a lesser extent in detecting male adult speech. In addition, the automated calculations turned out to be reliable for the amount of child vocalizations, but not for adult words. As for the child’s development, the main results are as follows: 1) the onset of variegated babbling was substantially delayed in twins, and their lexicon size and language scores remained lower than those of children in the normative data, although remained within normal variation. 2) Older siblings influenced family interaction with their own production, but also by activating fathers and reducing the time their infant siblings vocalize. 3) Twins with older siblings showed better language skills at the age of two years than first-born twins.

Based on the results, this study suggests that the reliability and validity of the LENA System needs to be further evaluated before it can be applied to clinical use in Finnish. In addition, the delayed onset of variegated babbling and its possible relations to, for example, later phonological development should be studied as well as the enhancing role of an older sibling.

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The dissertation is published in the publication series of Acta Universitatis Tamperensis; 2240, Tampere University Press, Tampere 2016. ISBN  978-952-03-0295-5, ISSN 1455-1616. The dissertation is also published in the e-series Acta Electronica Universitatis Tamperensis; 1740, Tampere University Press 2016. ISBN 978-952-03-0296-2, ISSN 1456-954X.

The dissertation can be ordered at: Juvenes e-bookstore or by e-mail: verkkokauppa@juvenesprint.fi.