I know that most languages start with many changes based on region and other languages influencing; but once a language has been established, what language hasn't changed much?

For instance, a branch of the Celtic languages like Welsh, or a branch of the Romance languages like the Catalan language. Have these changed much since they were established as a spoken language? Have any others?

Any languages that you know of that haven't changed much?

I know that most languages start with many changes based on region and other languages influencing; but once a language has been established, what language hasn't changed much?

For instance, a branch of the Celtic languages like Welsh, or a branch of the Romance languages like the Catalan language. Have these changed much since they were established as a spoken language? Have any others?

Any languages that you know of that haven't changed much?

I know that most languages start with many changes based on region and other languages influencing; but once a language has been established, what language hasn't changed much?

For instance, a branch of the Celtic languages like Welsh, or a branch of the Romance languages like the Catalan language. Have these changed much since they were established as a spoken language? Have any others?

Any languages that you know of that haven't changed much?