Samenvatting bilingualism (logopedie fase 3)

Samenvatting van de hoorcolleges van het OPO bilingualism uit fase 3 logopedie. Bevat alle info van de powerpoints, de cursus en eigen notities. Docent: Kirsten Schraeyen

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Samenvatting bilingualism

HC 1
Introduction
 Variety of definitions (depending on research perspective)
Speaking/using/understanding/fluency in more than 1 language (effectively)
 Bilingualism vs multilingualism
Children ánd adults
‘The coexistence of more than 1 language system within an individual, as contrasted
to monolingualism’
 Reasons for being bilingual
Multicultural and multilingual societies
Migration
(intentional choice)
Types of bilingualism
Two main types:
 Simultaneous bilingual individuals: exposed to 2 languages from birth or early in infancy
 Sequential/successive bilingual individuals: they learn 1 language first and learn an
additional language(s) at a later age (earliest from 3 years of age)
 Combination also possible
The distinction is important because we do see difference in language use ánd language knowledge
or proficiency profiles:
 throughout development
 in adulthood
Does bilingualism lead to structural brain changes?
• Monolinguals: structural brain changes from birth throughout the lifespan
specific developmental trajectories of grey and white matter
o Grey matter usually shows decreases between early childhood and early
adulthood, across cortical and subcortical structures with:
 Cortical thickness: decrease
 Cortical volume: increase followed by decrease
 Cortical surface: increase followed by decrease
 Subcortical structures: Decrease + increase/decrease (depending on
structures)
White matter: increase
 Bilinguals
Difference in brain structures between bilingual and monolingual adults
Bilingual adults: structural changes in cortical regions & subcortical grey matter
structures + in white matter tracts that connect these regions
Different patterns found depending on the L2 proficiency and use:
o Young adult bilinguals with limited experience using their 2nd language
showed:
 Increased cortical thickness/volumes in multiple frontal, parietal &
temporal regions  monolinguals
 Limited/no changes in subcortical volumes
 No white matter effect
o Young adult bilinguals with more L2 experience showed
 Greater subcortical volumes  monolinguals
 No difference in cortical regions 
 Increased white matter integrity
o Older bilingual adults:
 Greater grey matter volumes in cortical & subcortical regions &
greater white matter integrity in the same tracts as are found in
younger bilingual adults  monolinguals
 Comparison monolingual and bilingual individuals (3-21 years): both similar and different
development trajectories between both groups
Development similarities:
o BI & MO: continuous decreases in cortical thickness childhood 
adolescence
o BI & MO: cortical volume & cortical surface - early increase/stability 
decrease
o BI & MO: white matter integrity – increase over time childhood 
adolescence
o No difference observed for subcortical structures
Developmental differences
o Around age of 3: BI lower cortical thickness & volume  MO
o Around late childhood to early puberty: these values of thickness and
volumes converged
o At that point: BI diverged again from MO in showing larger values
o In some cortical areas: values for BI & MO reconverged in early adulthood
 Conclusion:
BI brain indeed differs from the MO brain and this difference begins to be apparent
during development
Over time = Structural brain changes in MO & BI
At certain points in time: different brain structures between MO & BI
Which language(s) is/are active in the bilingual brain?
• The native language is active when using the non-native
• The non-native language is active when the native one is used
 Language co-activation
 Interactions observed at all representational levels of language, even in monolingual
language contexts: Word reading/listening to speech/speech production
 Study: English-Russian bilinguals versus English monolinguals
MO: competition from English phonetically overlapping lexical items (target: spear;
competitor: speaker)
BI: competition from English ánd Russian phonetically overlapping lexical items
(target: spear; competitors: speaker & spichki)
 It proves that this activation in bilinguals = not limited to a single language, but activates
corresponding words regardless of the language to which they belong
 Consequence of this language co-activation: bilinguals have to inhibit possible lexical
competitors, not only from target language (as MO also have to do), but also from non-target
language(s)
 Which brain regions are activated for language processing  left cerebral hemisphere
 Which factors determine whether completely overlapping or somewhat distinct neural
systems underlie the processing of 2 languages in the bilingual brain?  age of language
acquisition, skill attained in each language, experimental tasks and level of analysis as well as
individual factors

How does the bilingual brain distinguish and control which language is in use?
 Language control  associated with the use of a complex set of inhibitory control
mechanisms
= quite effective in bilinguals
 The mechanisms underlying language inhibition: not well understood yet
Domain-general inhibitory mechanism (linguistic and non-linguistic)
o Handles language & non-language inhibitions
o Je onderdrukt dus ook niet-talige prikkels zoals een geluid of een geur die je
niet wil horen/ruiken
Domain-specific inhibitory mechanism (linguistic)
o Only focussing on inhibiting language elements
Series of independent linguistic inhibitory mechanisms (lexical competitors –
auditory FB - …)?
o Efficient bilingual speech production relies on different elements
They all believe BI are able to control their languages to achieve accurate verbal
output
More research needed to fully understand the underlying mechanisms of this
language control
The language control system ≠ unique to bilinguals, but they always have to use it to
suppress the other language
 Same/different brain regions?
Highly proficient bilinguals  activation same brain regions
Second language later in life  activation broader brain regions (only partially
overlapping in brain)