What programming language of News Website (BBC, Forbes…..)

Hi All
I’m newbie entry level in Web Develop.

My first client want to build a News Website with multiple topic like BBC, Forbes or NZ herald. I’m not sure what kind of programming language that those websites using.
Are they using website builder like WordPress, Wix to build a website or coding from scratch. What ‘s pros and cons of those language, cause they ask for secure system like Internet Banking Website too.