Richard Talley wrote:
LyX automagically typesets words like TeX and LaTeX using the special logo for those words.How do I turn this behavior off?
I see you already got some answers for how this is done for the entire document. If you want to do this for particular instances of LyX/TeX/LaTeX, just "Insert->Formatting->Ligature Break" somewhere inside the word you want to protect.
Or insert anything else that don't produce output, such as an empty TeX (ERT) box.