I am not sure if it is Amazon or my ISP but Alexa seems to be suffering a massive latency issue, it takes longer and longer to respond and sometimes even speaks as if the response is being played at half speed or less even.
I took my newest Echo device on holiday where the latency was superb and it was like new, so I did some very basic tests on fast.com while there to compare when I got back.
My network speed is adequate for my needs but the issue seems to be latency, I am not sure that OpenWrt can do anything about this as it is surely a function of the ISP service or their traffic shaping.