Dialect Test
The Dialect Test was created by A.J. Ellis in February 1879, and was used in the fieldwork for his work "On Early English Pronunciation". It stands as one of the earliest methods of identifying vowel sounds and features of speech. The aim was to capture the main vowel sounds of an individual dialect by listening to the reading of a short passage. All the categories of West Saxon words and vowels were included in the test so that comparisons could be made with the historic West Saxon speech as well as with various other dialects.
Explicit and implicit methods
Since the implicit method cannot be carried out for each kind of differential operator, it is sometimes advisable to make use of the so called operator splitting method, which means that the differential operator is rewritten as the sum of two complementary operators
while one is treated explicitly and the other implicitly.
For usual applications the implicit term is chosen to be linear while the explicit term can be nonlinear. This combination of the former method is called Implicit-Explicit Method (short IMEX ).