Sleep helps with learning new language: Study

Getting those eight hours of sleep can have linguistic benefits, according to a study that found it helped adults speak a new language.

While one sleeps, the brain is known to integrate or ‘consolidate’ information learnt during the day with previous knowledge to file it for long-term storage. Researchers, led by University of South Australia, tracked brain activity in 35 native English-speaking adults as they were learning a miniature language called ‘Mini Pinyin’, which is based on Mandarin but has grammar similar to English.

A miniature language is used in scientific experiments for studying aspects related to learning languages. Mini Pinyin “mimics natural language as it is based on an existing language (Mandarin Chinese) and includes both structure and meaning”, according to a 2020 study published in the journal ‘Behavior Research Methods ‘

In this study published in the Journal of Neuroscience, half the participants learnt Mini Pinyin in the morning and returned in the evening to have their memory tested, the researchers said.

The other half learnt Mini Pinyin in the evening and then slept in the laboratory overnight, while having their brain activity recorded. The team tested the participant’s progress in the morning.

Those who slept performed significantly better, compared to those who remained awake before the memory test.”We found that sleep relative to wake was associated with superior performance for rules that followed a sequence-based word order,” the authors wrote.

Improvements in memory because of sleep were related to the linking of slow oscillations and sleep spindles, which are brainwave patterns that synchronise during the non-REM phase of sleep, according to lead researcher Zachariah Cross, who did his PhD from the University of South Australia.

Non-rapid eye movement (REM) sleep is the restful phase of sleep when eyes stop moving and during which muscles relax, and brain activity, breathing and heart rate slow down. “This coupling (linking) likely reflects the transfer of learned information from the hippocampus to the cortex, enhancing long-term memory storage,” Cross said.

“Post-sleep neural activity showed unique patterns of theta oscillations associated with cognitive control and memory consolidation, suggesting a strong link between sleep-induced brainwave co-ordinations and learning outcomes,” the lead researcher added.

The researchers also said the findings could potentially inform treatments for individuals with language-related impairments, including autism spectrum disorder (ASD) and aphasia, who experience greater sleep disturbances than other adults.

Increasing slow oscillations could accelerate aphasia-based speech and language therapy, Cross said.