Question:

I've learnt very standard Japanese and was curious to know which dialect involved the following changes:

ございます　－＞　ございやす
いらっしゃいませ　－＞　いらっしゃいやせ

Answer:

dialect of Edo's merchant class people

ございます　→　ございやす　→　ごぜえやす

samurai dialect
ござりまする