How do some people develop the tendency to overuse particular words?

Solution 1:

It sounds like the word is being used as a bit of a filler word:

In linguistics, a filler is a sound or word that is spoken in conversation by one participant to signal to others that he/she has paused to think but has not yet finished speaking. ... Among youths, the fillers "like", "y'know", "I mean", "so", "actually", "basically", and "right" are among the more prevalent. Ronald Reagan was famous for beginning his answers to questions with "Well..."[citation needed], as President Barack Obama often begins statements with "Look...".[citation needed] Fillers fall into the category of formulaic language.