For reasons I don't understand, my brain is unable (at present) to communicate properly to my (fully working) voice box. My voice box was checked with a camera (down my nose) a few months ago.
Although my speech sounds OK to me (clarity and loudness) apparently it is a whisper and hard to understand. All the time I feel breathless.I am told this is all a result of my brain bleed and it will, in the end, recover. I have to be patient!
Although I can manage short speech periods on the air (VHF/UHF UKAC sessions, for 30-60 minutes and on our Monday 2m net for similar times) I find voice QSOs effortful, hence why I use WSPR and other digital modes a lot right now. Hopefully thing will improve in 2015.