I have written about this question in other posts that you find under Reflections and Recommendations on Learning and Teaching
There are quite a few linguists who share their research and insights on the internet in videos or podcasts. I have listed several of them below.
I have been going back into the literature of first, second and foreign language learning and came across an ‘old favorite’ – Stephen Krashen
Stephen D. Krashen – Language Acquisition (youtube.com)
Not everyone agrees with Krashen …
Below is a selected list of videos with interviews and presentations by experts in the field of language acquisition and language learning.
Professor Paul Nation: The Scientific Way To Learn Languages
Vocabulary Professor Explains How To Learn Languages | Dr. Norbert Schmitt
Professor Jeff McQuillan – Second Language Teaching: A Reading List