Just out of curiousity...
In our application I list all the available translations in the following format "NativeName - EnglishName". For some languages the NativeName isn't capitalized eg.
"Deutsch - German"
"español - Spanish"
"français - French"
"italiano - Italian"
"Nederlands - Dutch"
"polski - Polish"
It's no big deal to capitalize the first letter, but what is the reason behind this?