Answer: A rudiment is the basic principle of a skill, for example being taught the rudiments of English as a child. The fundamentals or starting of something. For example: The girls learned the rudiments of sewing while away at boarding school. Meaning, the girls learned the basics of sewing, more or less the minimum of the skill.
When the large cat repeats the same words 'Better wait till Martin comes' It creates excitement and curosity in the readers mind that who this Martin is? So, the effect that this repetitive words give to the story is that it pushes the story to it's most exciting part.