I read a lot and I know plenty of words. However, when I speak I use such a tiny percentage of the words I know, I bore myself! I use varied language in an academic context, but it feels so unnatural for me to speak in this way. My mother was not the brightest and the language used at home and in my immediate social circles was always quite limited. Going through university, moving to a new area, and mixing with other people, I've realised how limited my vocabulary is. I'm not talking about long, fancy words, but modest words that add a bit of colour and spice to shake things up a bit.
I know the answer people usually give is read more, but I read so much. The words are in my head but I just don't seem to be able to use them,