🪄 Created using NotebookLM, with all the benefits and blind spots of human editing.

In this episode of Codex Mentis, we unpack why learning a third language is not simply ‘second language learning, but easier’. Third Language Acquisition (L3) forces the brain to juggle two existing linguistic systems, creating a ‘two-blueprint’ problem where prior knowledge can help or hinder in unexpected ways. We explore cross-linguistic influence, including evidence that learners may borrow rules from the ‘wrong’ prior language, and the central idea of cognitive economy: the mind reuses what it already has, even when that reuse carries costs.

We then dig into the field’s main disagreement about how the brain chooses what to transfer: does it copy the overall grammar of the most similar known language, or negotiate feature by feature? To test this, researchers build tightly controlled artificial and semi-artificial languages that sidestep vocabulary learning and focus on grammar. Finally, we look at EEG findings showing that early stages of learning a new grammar rely more on attention and pattern detection than automatic, native-like processing, and we discuss an ongoing longitudinal study asking whether this deliberate processing can shift over time into the brain’s more implicit, automatic signature for grammar.

Sources and related content can be consulted at ⁠https://pablobernabeu.github.io/publication/third-language-longitudinal-data-artificial-language-learning-eeg