help..no voice prompts/guidance

hi,
i'm new to all this gps satnav etc..just got my v.first satnav,the icn510 and i have problems already...i cannot hear any voice prompts or guidance even though i have it enabled and the volulme on max.i'd appreciate any help in resolving this problem?...kindest regs gavin

p.s if you would email my personal email.. gavcav@hotmail .com ..as well,that would be great,thanks.