Sip Voip for Ipod Touch HELP?

ok so i have sip voip on my ipod and i called my house with it and it worked. But the only thing is when i pick up my house phone and talk into it i cant hear anything coming out of the speakers when they are connected to my ipod touch. and i know in order for me to talk with my ipod touch that i have to get a mic. but i have seen videos on youtube and i see ppl calling their own house and talking into it and they can hear it on their speakers. but i cant hear my self on my speakers that are connected to my ipod touch. HELLP

if that was hard to understand then heres this
ipod touch connected to external speakers
i use itouch to call house
i pick up house phone and talk into it
i cannot hear anything on my external speakers when volume is high

what the ef do i do >>??