"Most of their conversation was complaints about the company."

Question

I am a native English speaker and have gone through 8 years of grammar school (and 20-some years of speaking...). Nevertheless, sentences such as the one in the title have always sounded odd to me and I've never been sure if they are in fact grammatical.

To explain my question more generally (and perhaps helpfully for ESL students), in English, nouns that represent generic quantities (most, some, all, etc.) can be considered either singular or plural depending on the context. When the context is not clear, whether those nouns are singular of plural is often determined by a prepositional phrase.

Most of the cows are white (most is plural)

Most of the cow is white (most if singular)

This is relatively clear and straightforward. An interesting problem occurs though when a singular "most" is composed of something plural (as in the title of this post).

In that case, the "conversation" (a singular noun) is composed of "complaints" (a plural noun). So to convey the correct intention, it seems necessary to construct a sentence that has a singular noun in the subject, and a plural noun in the complement which goes against subject complement agreement rules.

Furthermore, the possible alternatives all convey something different:

All of their conversations were complaints (wrong because it states that there were multiple conversations)

All of their conversation was a complaint (wrong because it only states that there was one complaint and I wish to state there were multiple)

Is this in fact an exception to subject complement agreement rules or are sentences like the above unacceptable in proper English?

Answer 1

Most of their conversation was complaints about the company.
most of their conversation consisted of complaints about the company

is understandable with the meaning of multiple complaints within a single conversation, which is your desired intent.

Most of their conversation was complaint about the company.

follows the guideline

when the complement is shared by all constituents of the plural subject, it remains singular

You could also reword your sentence to be less ambiguous

Most of their conversation was complaining about the company.
Their conversation was mostly complaints about the company.

both imply many complaints in one conversation.

Answer 2

You seem to have a good grasp of the nuance, so I'm not certain how much help I can be. This kind of subject-verb agreement plagues native speakers as well.

Of course, the easiest way to resolve the apparent lack of congruity is to avoid it entirely by rewriting the sentence so that conjugation is obvious:

Their conversation consisted mostly of complaints about the company.

But this also avoids your question. The simple answer is that if conversation is the subject, and since it is singular, the verb should match. "Most of the conversation" is still singular. "All of their conversation" is odd phrasing, but would still be singular. And so on.

I think your example only seems exceptional because of the odd phrasing. To avoid confusion, again, I would say it differently. But, if you must phrase the sentence this way, consider this similarly odd example:

Most of Indonesia is islands.

The subject is "Indonesia" (or "most of Indonesia") which, although made up of many islands, is still a singular nation. In the same way your "conversation", although make up of many complaints, is still a singular entity.