How can you say anything about complex people by a consideration of simple people? How can you make your shepherds credible? Isn`t the dress of the shepherd only a masquerade sometimes?
Should a poet make use of dialect in composing a pastoral? Doesn`t it violate the rules of decorum? Spenser uses a kind of English Doric: his shepherds talk like shepherds sometimes and sometimes like poets, "high" topics such as love demand for "high" language, "low" topics require for the usual banter.