It seems you have improved a bit over the summer but now talking issues. The radiation can affect our ability to speak in that it takes a steady control of breath to operate the vocal cords for word sounds. Radiation and or nerves damaged result in vocal issues for a while. Hopefully, as in my case, this is temporary. Although I did seek out a speech and hearing tech, there was nothing that could be done that time itself wouldn't take care of.
Now, if it's a case of a "brain fart" where you lock up and cannot get the word to the voice box, that can also be an after shock of the radiation. Likely however it is simply the control of the larynx which should improve in time. For most of us, issues like this and others can go on for years. Eventually, and it seems around the time we get used to something weird going on, the problem goes away. I did a dissertation a while back on some side effects of radiation and the time period involved. These effects were not uncommon nor unduly lengthy as most would attest. Cancer, the gift that keeps on giving. I think when we learn to deal with all of this we actually learn to deal with just about anything life throws at us.