Code - mixing is the use of two languages at the same time or rather change of language at the same time. Let me give you example of both to make it clearer.

Example of Code Mixing:

Yeh train ka time change ho gaya hai kya?

If you notice in these particular sentences there is mix of Hindi and English. This is an example of code - mixing. In advertisements, TV commercials, and day-to-day conversations we can get numerous examples of code - mixing.

Code-mixing has given rise to new languages like Hinglish (Hindi + English) Tanglish (Tamil + English)

Radio jockeys and TV anchors deliberately mix English words with stream of Hindi sentence to sound more hep and funky.