In fact it is doubtful whether we can properly use the term "English dialect" either, since the English language is a very recent import to this part of the world. The differences in speech from standard English are the result of our grandparents' struggles to learn a foreign language forced on them by a school system hostile to the Welsh language and by an influx of English immigrants who refused to learn the language of the country they had moved to.
The point of your original front-page article which started this discussion was that the English dialects are under threat from standardisation of speech. The same process has been happening with the Welsh dialects through the influence of the standard Welsh used in school and on television and radio, though to a much lesser extent.
There is still a rich variety of dialects in Welsh, the differences being most marked between the North and South of the country. Perhaps one reason for this is that in Welsh we do not seem to have any connotation of social class difference between one dialect and another. All are equally acceptable.
R N BEYNON