Learn English – the proper plural of “reputation”

The official rule is: if it acts as a singular unit, it gets a singular congugation; if it acts as a group of individuals viewed individually, it gets a plural congugation. There is no difference between common and proper nouns.

For example, Seventy dollars is too much to spend on a DVD. (The seventy dollars is one unit)

In relation to the example above, The Bangles is an awesome group. (one unit) BUT.. The Bangles are awesome, especially Susanna Hoffs! (looks at each individual group member)

It gets complicated because it seemingly leaves it up to the speaker to determine how the unit is being referenced.

The Latin plural of the noun apparatus is actually apparatus. (Sometimes the Latin is spelled singular apparātus and plural apparātūs; the vowel lengthens in the plural, but that's not usually reflected in the spelling.) This is because it's fourth declension. In the 18th and 19th centuries, when most educated English speakers had studied Latin, apparatus was sometimes used as the plural; I believe this usage is quite rare today.

With status, apparatus, and other Latin nouns of the fourth declension ending in -us, the English plural adds an -es. The Latin nouns which pluralize by turning an -us into an -i, like radius, fungus, alumnus, are all second declension. For some Latin nouns of the second declension, like campus, the Latin plural has been lost, and the English plural adds an -es. But campi would be correct in Latin, while apparati is incorrect in both English and Latin.

You don't actually hear the English plural apparatuses that often, because apparatus is often treated as a semi-uncountable noun: one apparatus, two pieces of apparatus. (See Google Ngrams.) I assume this usage developed because people didn't know whether to use apparatus or apparatuses for the plural, and figured out a way of avoiding the issue altogether.