PublikationerI urval från Stockholms universitets publikationsdatabas
2016. Kristina Nilsson Björkenstam, Mats Wirén, Robert Östling. The 54th Annual Meeting of the Association for Computational Linguistics, 82-90
How do infants learn the meanings of their first words? This study investigates the informativeness and temporal dynamics of non-verbal cues that signal the speaker's referent in a model of early word–referent mapping. To measure the information provided by such cues, a supervised classifier is trained on information extracted from a multimodally annotated corpus of 18 videos of parent–child interaction with three children aged 7 to 33 months. Contradicting previous research, we find that gaze is the single most informative cue, and we show that this finding can be attributed to our fine-grained temporal annotation. We also find that offsetting the timing of the non-verbal cues reduces accuracy, especially if the offset is negative. This is in line with previous research, and suggests that synchrony between verbal and non-verbal cues is important if they are to be perceived as causally related.
2016. Mats Wirén (et al.). The 54th Annual Meeting of the Association for Computational Linguistics, 44-52
One of the characteristics of child-directed speech is its high degree of repetitiousness. Sequences of repetitious utterances with a constant intention, variation sets, have been shown to be correlated with children’s language acquisition. To obtain a baseline for the occurrences of variation sets in Swedish, we annotate 18 parent–child dyads using a generalised definition according to which the varying form may pertain not just to the wording but also to prosody and/or non-verbal cues. To facilitate further empirical investigation, we introduce a surface algorithm for automatic extraction of variation sets which is easily replicable and language-independent. We evaluate the algorithm on the Swedish gold standard, and use it for extracting variation sets in Croatian, English and Russian. We show that the proportion of variation sets in child-directed speech decreases consistently as a function of children's age across Swedish, Croatian, English and Russian.