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Anna PerssonAdjunkt

Om mig

Jag arbetar som adjunkt i svenska som andraspråk vid institutionen för svenska och flerspråkighet. Jag disputerade i nordiska språk i november 2024 på en avhandling som undersöker huruvida hypotesen om normalisering av den akustiska talsignalen kan bidra till vår kunskap om hur hjärnan hanterar talspråklig variation vid lyssnares bearbetning och förståelse av ett språks (i detta fall, svenska och engelska) vokaler. Mitt grundläggande forskningsintresse rör förståelsen av hur människor processar talat språk, mer specifikt hur hjärnan kan hantera det faktum att vi alla varierar i vårt uttal. Jag använder mig av akustisk analys av talat språk, perceptionsexperiment och datorbaserade modeller för att undersöka de underliggande kognitiva mekanismer som möjliggör stabil talperception.

Jag har en bakgrund som lärare i svenska som andraspråk inom gymnasieskolan och vuxenutbildningen, samt som provkonstruktör och bedömare av Tisus (Test i svenska för universitet- och högskolestudier).

Undervisning

Eget kursansvar:

  • Psykolingvistik för ämneslärare i svenska, språkkonsultprogrammet och studenter i svenska 2.
  • Bedömning av språkfärdighet, kurspaket 2 Svenska som andraspråk.
  • Skriftlig färdighet och läsförståelse, Behörighetsgivande kurs i svenska som främmande språk.

Forskningsprojekt

Förstaspråkstalares anpassning till andraspråkstal

Förstaspråkstalares anpassning till andraspråkstal. Datamodellering och experimentella ansatser på vokalperception. Projektet undersöker hur vår talperception hanterar det faktum att vi alla varierar i hur vårt uttal.

Forskning

Publikationer

I urval från Stockholms universitets publikationsdatabas

  • Evaluating normalization accounts against the dense vowel space of Central Swedish

    2023. Anna Persson, T. Florian Jaeger. Frontiers in Psychology 14

    Artikel

    Talkers vary in the phonetic realization of their vowels. One influential hypothesis holds that listeners overcome this inter-talker variability through pre-linguistic auditory mechanisms that normalize the acoustic or phonetic cues that form the input to speech recognition. Dozens of competing normalization accounts exist-including both accounts specific to vowel perception and general purpose accounts that can be applied to any type of cue. We add to the cross-linguistic literature on this matter by comparing normalization accounts against a new phonetically annotated vowel database of Swedish, a language with a particularly dense vowel inventory of 21 vowels differing in quality and quantity. We evaluate normalization accounts on how they differ in predicted consequences for perception. The results indicate that the best performing accounts either center or standardize formants by talker. The study also suggests that general purpose accounts perform as well as vowel-specific accounts, and that vowel normalization operates in both temporal and spectral domains.

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  • Comparing theories of pre-linguistic normalization for vowel perception

    2024. Anna Persson.

    Avhandling (Dok)

    The present thesis compares competing theories of pre-linguistic normalization for the perception of Swedish and English vowels. Specifically, the overall aim is to investigate whether normalization might be key to understanding the mechanisms supporting robust cross-talker perception, and to gain more insights into the specific computations involved. The thesis is based on three articles that employ acoustic analysis, behavioral experiments and computational modeling to address the question of vowel normalization.

    Article I uses a novel phonetically annotated database of Swedish vowel recordings, the SwehVd, to provide an updated acoustic description of the Central Swedish vowel system and to evaluate certain claims of cue-to-category mappings introduced by previous work. Replicating previous studies, the results of Article I suggest that F1, F2 and vowel duration are the most important cues to vowel identity in Central Swedish. In addition, the results highlight the importance of formant dynamics for reliable category distinctions. The acoustic characteristics of Article I further constitute the input to the computational modeling presented in Article II.

    Article II evaluates 15 competing normalization accounts in terms of how well they predict the intended vowel category of Central Swedish, as represented by the talkers in SwehVd. Specifically, a computational model of vowel perception, a Bayesian ideal observer, is used to assess the predicted consequences of normalization. The results indicate that normalization accounts that assume the learning and storing of talker-specific acoustics (i.e., extrinsic accounts) achieve the best fit against vowel production data. The evaluation against the SwehVd database further contributes to the insight that languages with dense vowel spaces do not necessarily require more complex normalization mechanisms.

    Article III evaluates 20 different normalization accounts in how well they predict listeners' categorization behavior in two vowel categorization experiments on US English vowels. Paralleling the results from Article II, the results indicate that more complex extrinsic normalization is needed for robust cross-talker perception. However, it is a computationally minimalist extrinsic account – uniform scaling – that provides the best fit when evaluated against listeners' responses. This would seem to suggest that more complex computations (as in, e.g., Lobanov normalization) are not required for human speech perception.

    The thesis aimed for a broad-scale evaluation of competing theories of pre-linguistic normalization, assessing the predictions of different accounts using different types of experiment stimuli, different vowel spaces, and different sets of acoustic cues. This broad-scale evaluation was made possible through the implementation of a holistic and stringent computational framework, for an unbiased comparison of accounts. The main contributions of this thesis include the open-access publication of the framework and the vowel database, to facilitate replication and future studies.

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  • The acoustic characteristics of Swedish vowels

    2025. Anna Persson. Phonetica 81 (6), 599-643

    Artikel

    The Swedish vowel space is relatively densely populated with 21 categories that differ in quality and quantity. Existing descriptions of the entire space rest on recordings made in the late 1990s or earlier, while recent work in general has focused on subsets of the space. The present paper reports on static and dynamic acoustic analyses of the entire vowel space using a recently released database of h-VOWEL-d words (SwehVd). The results highlight the importance of static and dynamic spectral and temporal cues for Swedish vowel category distinction. The first two formants and vowel duration are the primary acoustic cues to vowel identity, however, the third formant contributes to increased category separability for neighboring contrasts presumed to differ in lip-rounding. In addition, even though all long-short vowel pairs differ systematically in duration, they also display considerable spectral differences, suggesting that quantity distinctions are not separate from quality distinctions in Swedish. The dynamic analysis further suggests formant movements in both long and short vowels, with [e:] and [o:] displaying clearer patterns of diphthongization.

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