While finding out a PHP converter, which converts different parts of text into noun, like from verb to noun, I found a great solution in algorithm known as Porter Stemming Algorithm. Though this type of script is needed when you want to match the words of different forms, and treat them as one single word, like in counting, as it will try to cut some of the ending characters of the word and make them look similar, to be treated as one.

Convert Parts of Text Into Noun

If you are finding a script in PHP or any other language like Java, Perl, Python, VB, Javascript etc, which will let you convert words like verb into noun, plural into singular, past tense into present tense, all you need to do is to get the Porter Stemming Algorithm from the following website link:
Porter Stemming Algorithm

By using this website, all you need to do is to download your specific language’s script (which is a text file over there), and copy the functionality into your code and start using the function for converting different forms into noun.