No icons in the skill tree and no text in dialogue options

That's missing shaders (or compile error). Assuming you use PC version, delete everything you find in c:\Users\[uername]\AppData\Local\D3DSCache\

Depending on what video card you have, increase (or set) the shader cache size to >5gb and try to clear the video card's shader cache

for nVidia: c:\Users\[uername]\AppData\LocalLow\NVIDIA\PerDriverVersion\DXCache\

for intel: c:\Users\[uername]\AppData\LocalLow\Intel\ShaderCache\

For AMD I'm not sure about the path so maybe some one can add the information.

After cleaning the cache from APPDATA the game will rebuild the shaders and the icons and text should be back. The most important location to be clear is c:\Users\[uername]\AppData\Local\D3DSCache\

Also, don't touch the game's shaders cache or the game will be forced to repair mode.