Synchronic variation is language variation at one point in time and is usually called dialect
variation. The difference between British and American English is an example
of synchronic variation.
Diachronic variation is language variation between two points in time
and is usually referred to as language change. The difference between
old English and modern English is an example of diachronic variation.
Teaching about both kinds of language variation is part of our effort to improve education through providing an accurate understanding of how language works. The idea that variation and change are a natural part of language is important, and can help teachers and students alike to gain a new perception of the English language and all of its dialects.
For more lesson plans, visit our Dialects in Schools page.