A £5m research centre to study bilingualism is to be set up at the University of Wales in Bangor.
The centre puts Bangor "at forefront" of international research
A five-year project will then examine the relationship between two languages in individuals and within communities both within the UK and internationally.
Researchers hope their work will influence public perceptions and the formulation of policies.
Professor Merfyn Jones, vice-chancellor of Bangor, said the investment was a "real vote of confidence".
"This is a major development that will no doubt influence the public perception of bilingualism and the formulation of language and educational policy, not only in Wales but worldwide," said Professor Margaret Deuchar, of the School of Linguistics and English Language.
The fact that the Bangor was a "well established Welsh-English bilingual community" would act as a springboard for extending the expertise to other bilingual communities, she added.
Researchers will look at the individual bilingual mind, language use and development and the bilingual community and whether being able to speak two languages is an advantage for a person through life.
Professor Colin Baker from the university's School of Education said the new centre would put Wales and the University of Wales in Bangor at the forefront of international research on bilingualism.
"Wales is regarded as a world-wide leader in language planning and bilingual education," he said.
"This centre celebrates that leadership and will ensure Wales will continue to innovate and enhance bilingual policy and practice both nationally and internationally," he said.