Introduction
The neural background of language learning is still quite uncertain. There is no specific definition for language learning as it concerns too many areas. In simple terms it can be defined as acquiring the ability to communicate in your mother tongue or a second/foreign language.
Recently focus has been put on bilingualism as more and more people are exposed to multiple languages. This is due to a greater exposure with technology, immigration and ethnic diversity.
The brain regions that are relevant for language are located in the inferior frontal and temporal cortices with dominance in the left hemisphere.
These cortices are connected via ventral and dorsal pathways with the ventral pathway mainly for auditory-to-meaning mapping, this is the process the brain goes through in connecting the auditory sound of a word to its meaning. The dorsal pathway supporting auditory-to motor mapping, this is the association between of the sound of the word and the brains skills used for articulatory purposes.
Recent evidence suggests that the dorsal pathway is also involved in syntactic processing, in particular when sentences are complex. The dorsal pathway connects the temporal cortex to the premotor cortex (PMC) via the inferior parietal cortex (IFC) and parts of the superior longitudinal fasciculus (SLF). The ventral pathway connects the temporal cortex to Brodmann Area (BA) 44, which is located in the frontal cortex as is specific to humans and other primates, as part of Broca’s area via the arcuate fasciculus (AF). The ventral pathway also seems to be responsible for more than one function: it is assumed to support sound-to-meaning mapping , as well as local syntactic structure building or syntactic processes in general.
The ventral pathway consists of two fiber tracts that run closely together: the uncinate fasciculus (UF), which connects the anterior ventral inferior frontal cortex to the temporal pole, and the extreme capsule fiber system (ECFS), which mediates the inferior fronto-occipital fasciculus (IFOF), connecting the inferior frontal cortex along the temporal cortex to the occipital cortex.
The present model of the brain assumes two functionally and (partly) structurally different dorsal pathways, and considers two ventral pathways in their possible relevance for semantic and syntactic processing during language comprehension.