What you want to do is spell out numbers using English words. That's what you should have explained in the first place.
There is no such "function" in any language. You need to do the grunt work yourself and come up with a lot of code for each digit and each place value. Start by converting the number to a string and extracting each character one by one. Then write several subprocedures to translate each character to a word, depending on its place value. Then you will need to concatenate the words to a string corresponding to the full number.
Do it little by little, starting with numbers up to 9, and then up to 99. By then, you should have the hang of it. Good luck.