Phrases like "slip into the accent" really piss me off. You may have some sounds that you assosciate with a context but it is no more than that. We each have our own individual accents and a memory bank of others, more often than not erroneous stereotypes.

When most people sing or speak they try and establish points of cotact with what they are trying to communicate. Sometimes these are particular sounds but "slipping into" one accent or another is always bogus