These two sentences are different in that the first refers to a singular subject noun and the second is referring to a plural one. In the second sentence the subject of the sentence is plural, and this is expressed by means of reduplication ("person-person-person"). Reduplication is one of the ways of expressing plural number, number distinction may also appear in verbs.
"I will buy books for all my family at Christmas."
"I will buy a book for each member of the family at Christmas."
In these two examples, we see different ways of indicating plural action. In the first sentence the plural object is treated as a collective group, whereas in the second sentence it is the sequence of each one of its elements.