I have purchased a brand new Garmin Nuvi 660 &

I have purchased a brand new Garmin Nuvi 660 & Installed the latest 2010 maps. This unit is not pronouncing streets correctly. It is combining the whole street name & type eg. "Bell Street" is being said as "Bellst" and does it with nearly every street. I have another 3 of these unit using the same maps & the same voice and all the others are fine?? Can't understand any street names when she says them like this.