Academics have made a plea for people to "give their Welsh" as part of the biggest ever corpus - or collection - of the language.
The National Corpus of Contemporary Welsh project hopes to document 10 million expressions and words of everyday slang and formal Welsh.
The first project of its kind, its aim is to capture Welsh, in all its forms, across generations and regions.
Speakers will be able to add their contribution via a new app.
It is hoped the corpus will further understanding of the many different Welsh dialects and regional variations, and help learners.
"If you are teaching the language, you need to be sure you are teaching the words most learners are likely to hear," explained Steven Morris of Swansea University.
"The corpus helps us understand which phrases and words are used most often."