If you want to insert pauses between all words based on the silence level between words, try this Extend Silences plugin.
Audacity does not have any way to find instances of the same pitch that I know of, unless someone has written an experimental plugin. There is an experimental plugin to find instances of the same word, based on intonation Need pointers on adding feature to search pattern - #3 by Robert_J_H
What exactly is your end purpose? Your written text is not the same as counting all the words in a song. You can sometimes find all the beats in a song, if it has an aggressive beat.
Gale