The quality of outbound calls to telephones ("Skype Out" I think) has dropped markedly recently. My respondants can't hear me about half the time. The quality seems to come and go by the week.
As someone who works in the VoIP mobile client area for 7 years (though not for Skype) I have to be fair and say that this is unlikely to be Skypes fault.
They are known to use state of the art codecs so most likely the issue lies in the PSTN network that you are calling into.
For the out calling feature they are relying on Carriers all around the world for the VoIP -> PSTN functionality.
It would be another thing if you said that VoIP -> VoIP quality has dropped, here Skype has somewhat more control, although still not perfect control as they rely on the quality of Internet connection between caller and callee.
If the destination number is in the t-mobile network then they can't chose that the call doesn't go into t-mobiles network.
They can control one part of it, the point where their VoIP is transcoded and switched into the network, here could lie the issue. But the issue could also come from the destination end of the network.
I generally believe that US and EU carriers are solid enough that calling there shouldn't cause issues, but who knows whom the parent is calling.
Could be Afghanistan for all I know and I am not as confident here that there wont be any issues that are definitely out of control for Skype.
In some cases the carrier might even wilfully degrade the quality because they want to earn more. They earn less if Skype routes a caller from the US to Afghanistan via IP and lets him call from a Afghan to Afghan number.
