Plasticity in speech perception – effects of learning, age and bilingualism

Brain plasticity enables us to learn to perceive languages. Theories and models of non-native language learning predict learning difficulties in phonological areas where the native and non-native phonological systems overlap and where a category boundary of one language may lie somewhere within a category of another language. Phonologically, these areas are interesting within the two native languages of bilinguals from birth also. In this thesis, both psychophysiological and behavioural measurements were used to explore the neural plasticity in relation to learning, age, and bilingualism. The research questions were, whether phonological processing is different between different kinds of bilinguals and whether it is different between bilinguals from birth and monolinguals. A further research question was, whether different background factors, such as manner and age of learning, affect memory trace formation. The bilinguals from birth, simultaneous bilinguals, seem to have a shared phonological system for the two languages, whereas later bilinguals, sequential bilinguals, seem to have separate phonological systems for the languages. The shared system in the simultaneous bilinguals leads to slower processing compared to sequential bilinguals and monolinguals. The languages seem to be active all the time in the shared phonological system irrespective of the language context. Whereas the sequential bilinguals, with the separate systems, can even ignore their native language in a second language context. The studies on the manner and age of learning revealed that both classroom and laboratory training lead to similar functioning of memory traces. The laboratory training effects also seem to be permanent. However, the age of learning affects memory trace formation: While the young adults show memory trace formation during laboratory training, the elderly do not show the same effect. In conclusion, different types of bilinguals process speech differently and simultaneous bilinguals’ speech processing is different from that of monolinguals’. Training in classroom and in laboratory lead to similar functioning of memory traces. Age, however, affects plasticity and laboratory training does not lead to similar training effects in the elderly compared to young adults.Plastisiteetti puheen havaitsemisessa – Oppiminen, ikä ja kaksikielisyys Kielen omaksuminen tai oppiminen on mahdollista muovautuvien aivojemme vuoksi. Vieraan kielen oppimisteoriat ennustavat oppimisvaikeuksia sellaisilla fonologisilla alueilla, joilla äidinkielen ja vieraan kielen äännejärjestelmät ovat limittäiset eli alueilla, joilla toisen kielen äännekategorian raja sijoittuu toisen kielen äännekategorian sisään. Tällaiset fonologiset seikat ovat mielenkiintoisia myös syntymästään asti kaksikielisten kohdalla. Tämän tutkimuksen tarkoituksena oli tutkia neuraalista muovautuvuutta vieraan kielen havaitsemisessa oppimisen, iän ja kaksikielisyyden suhteen käyttäen sekä psykofysiologisia että behavioraalisia menetelmiä. Tutkimusten oli toisaalta tarkoitus selvittää, eroaako puheen neuraalinen prosessointi samanaikaisilla ja peräkkäisillä kaksikielisillä sekä eroaako puheen havaitseminen samanaikaisilla kaksikielisillä ja yksikielisillä. Toisaalta selvitettiin, muokkaantuuko yksikielisten puheen prosessointi samankaltaiseksi kuin peräkkäisillä kaksikielisillä kuuntele ja toista harjoittelun myötä ja ovatko harjoittelun vaikutukset pysyviä. Lisäksi selvitettiin eri taustatekijöiden –oppimistavan ja -iän – vaikutuksia muistijälkien syntyyn. Tutkimusten mukaan samanaikaisilla kaksikielisillä näyttää olevan yksi yhtenäinen fonologinen järjestelmä, kun taas peräkkäisillä kaksikielisillä näyttää olevan kaksi erillistä järjestelmää. Yhtenäisessä järjestelmässä molemmat kielet ovat koko ajan aktiivisia kielikontekstista riippumatta, mikä hidastaa prosessointia suhteessa erilliseen järjestelmään. Peräkkäiset kaksikieliset taas voivat toisen kielensä kontekstissa jättää äidinkielensä täysin huomiotta. Oppimistapaan ja -ikään liittyvät tutkimukset osoittivat luokkahuone- ja laboratorioharjoittelun johtavan samanlaiseen muistijälkien toimimiseen. Laboratorioharjoittelun vaikutukset näyttivät myös olevan pysyviä. Oppimisikä vaikuttaa kuitenkin muistijälkien syntyyn eri tavoin: nuorille aikuisille syntyy muistijäljet laboratorioharjoittelun vaikutuksesta, mutta vastaavaa ei nähdä iäkkäämmillä, jo eläkkeellä olevilla henkilöillä. Näyttää siis siltä, että eri tyyppiset kaksikieliset prosessoivat puhetta eri tavoin ja että samanaikaisten kaksikielisten puheen havaitsemisen prosessointi eroaa yksikielisistä. Kuuntele ja toista harjoittelulla voidaan saavuttaa puheen neuraalisen prosessoinnin taso, joka on samankaltainen kuin peräkkäisillä kaksikielisillä. Ikä kuitenkin vaikuttaa muovautuvuuteen eikä sama harjoittelu toimi iäkkäämmillä henkilöillä samalla tavalla kuin nuorilla aikuisilla

Phonetic training and non-native speech perception - New memory traces evolve in just three days as indexed by the mismatch negativity (MMN) and behavioural measures

Language-specific, automatically responding memory traces form the basis for speech sound perception and new neural representations can also evolve for non-native speech categories. The aim of this study was to find out how a three-day phonetic listen-and-repeat training affects speech perception, and whether it generates new memory traces. We used behavioural identification, goodness rating, discrimination, and reaction time tasks together with mismatch negativity (MMN) brain response registrations to determine the training effects on native Finnish speakers. We trained the subjects the voicing contrast in fricative sounds. Fricatives are not differentiated by voicing in Finnish, i.e., voiced fricatives do not belong to the Finnish phonological system. Therefore, they are extremely hard for Finns to learn. However, only after three days of training, the native Finnish subjects had learned to perceive the distinction. The results show striking changes in the MMN response; it was significantly larger on the second day after two training sessions. Also, the majority of the behavioural indicators showed improvement during training. Identification altered after four sessions of training and discrimination and reaction times improved throughout training. These results suggest remarkable language-learning effects both at the perceptual and pre-attentive neural level as a result of brief listen-and-repeat training in adult participants.</p

Advanced English learners benefit from explicit pronunciation teaching: an experiment with vowel duration and quality

Pronunciation skills are a key feature in overall oral communication skills. Without adequate pronunciation skills language learners might be misunderstood in communicative situations. This cross-sectional study focused on learning vowel duration and quality in L2 English. The subjects were advanced Finnish learners of English, whose production was compared to a native group before and after teaching. Our results suggest that explicit pronunciation teaching made the subjects’ pronunciation of L2 vowel qualities more native-like. Both of our subject groups mastered vowel duration on a native level, which suggests that learners who are used to different degrees of vowel duration in their L1 can transfer those features into L2 even if they are used functionally differently. Our study suggests that vowel duration is easier than vowel quality for Finnish learners of English. The study also showed the positive effect of pronunciation teaching for advanced learners

Motoric training alters speech sound perception and production – active listening does not lead into learning outcomes

Accurate speech-sound perception and production are prerequisites for communication in a non-native language. Earlier research has shown that new categorization and pronunciation patterns evolve in different learning settings and that these skills can be trained with various methods. We tested the effects of two types of training protocols on the production and identification of L2 vowels embedded in a pseudo-word context. Group 1 (Producers) participated in a listen and repeat training, where they produced the target stimulus /tᵾ:ti/ and the non-target stimulus /ty:ti/ after the example in a pseudo-randomized order; Group 2 (Listeners) was instructed to count the number of targets /tᵾ:ti/ in the same stimulus train without any motoric production movements. The results showed clearly that listen and repeat training led to plastic changes both in production and in identification, while no learning effects were obtained with the listening paradigm. This suggests a significant role of motoric experience in the acquisition of speech.Peer reviewe

Two types of bilinguals – Two types of production contexts

Language context affects different kinds of bilinguals differently at the preattentive level in speech perception. Bilinguals from birth (balanced bilinguals) perceive their languages in both language contexts similarly, which indicates that they have one unified phonological system. In contrast, bilinguals who have learned their second language in a classroom (dominant bilinguals) perceive speech according to separate, language specific systems and have separate phonological systems for the two languages. The present study focuses on speech production in similar kinds of bilinguals. We used three different language contexts, monolingual Finnish and Swedish and a bilingual context, in speech production tasks. Language context effects are seen in speech production of both bilingual groups. The difference in mother tongue identity is also shown as the dominant bilinguals differ from the balanced bilinguals in the production of Swedish vowels between monolingual and bilingual language contexts.</p

Aging and non-native speech perception: A phonetic training study

Cognitive decline is evident in the elderly and it affects speech perception and foreign language learning. A listen-and-repeat training with a challenging speech sound contrast was earlier found to be effective in young monolingual adults and even in advanced L2 university students at the attentive and pre-attentive levels. This study investigates foreign language speech perception in the elderly with the same protocol used with the young adults. Training effects were measured with attentive behavioural measures (N=9) and with electroencephalography measuring the pre-attentive mismatch negativity (MMN) response (N=10). Training was effective in identification, but not in discrimination and there were no changes in the MMN. The most attention demanding perceptual functions which benefit from experience-based linguistic knowledge were facilitated through training, whereas preattentive processing was unaffected. The elderly would probably benefit from different training types compared to younger adults. Keywords: Training; Speech perception; Phonological processing; Aging; Mismatch negativity (MMN)</p

Äidin tyypin 1 diabeteksen vaikutus sikiön ja vastasyntyneen terveyteen

Vertaisarvioitu. English summary.Tyypin 1 diabetesta sairastavan naisen raskauteen liittyy merkittävästi suurentunut obstetristen komplikaatioiden ja vastasyntyneen hoidontarpeen riski. Viidesosa tyypin 1 diabetesta sairastavien äitien lapsista joutuu vastasyntyneiden teho-osastolle ja joka toinen lastenosastolle hoitoon synnytyksen jälkeen. Tavallisimpia ongelmia ovat hypoglykemia, makrosomia ja siihen liittyvät synnytysvauriot, vastasyntyneen hengitysongelmat, hyperbilirubinemia ja ennenaikaisuus. Tyypin 1 diabetesta sairastavan naisen raskaus vaatii huolellista suunnittelua ja diabeteksen hoidon optimointia ennen raskautta sekä tiivistä moniammatillista seurantaa raskausaikana. Uudet kansainväliset hoitosuositukset korostavat glukoosipitoisuuden vaihtelun vähentämisen merkitystä. Raskauden suunnittelussa ja raskausajan hoitotavoitteena tuleekin olla riittävä aika glukoositavoitteessa (time in range, TIR). Jatkuvan glukoosiseurannan avulla voidaan vähentää äidin glukoosipitoisuuden vaihtelua ja vastasyntyneen ongelmia.Peer reviewe