Plural of noun and concept takes singular verb?

Why does a pairing of a noun and phrase about it, specifically with a question word, take a singular verb?

Generically: [Noun] and [idea about noun] [singular verb].†

Example: Language and how we use it has always fascinated me.

Why is the verb singular? Because there are two subjects it would seem that the verb should be plural. If the second subject was another noun, the verb would certainly be plural: The bike and its evolution are interesting.

My best conjecture is that there is actually only one subject and that the second apparent subject actually just specifies the relevant aspect of the first subject. Perhaps better punctuation would be parentheses: The bicycle (and how it evolved) is interesting.

† Perhaps this construction is wrong and this whole question irrelevant. I am not claiming it is the cleanest expression of the idea, but only that it is a more valid construction than with a plural verb. I am relying on its sounding right, and a plural verb's sounding wrong. How something sounds to one person isn't sufficient evidence, but I haven't found a good way to search for examples of either.