what rude verb slouches toward bethlehem to be born?

BACKGROUND:
My signature line reads “in principio erat verbum, substantivum enim nondum natum erat.” This roughly translates as “In the beginning was the word/verb, for the substantive/noun hadn’t been born yet.” The joke here, a reference to the first line of John in the Bible (“In the beginning was the word”), plays on the ambiguity of verbum, which can mean “word” or “verb.”

But maybe I got it all wrong. Maybe it was the noun that was first, all along?

QUESTION:

In reading Allen & Greenough’s New Latin Grammar (as found here, I came across the following statement:

A Verb is a word which is capable of asserting something: as, sum, I am; amat, he loves.

NOTE.–In all modern speech the verb is usually the only word that asserts anything, and a verb is therefore supposed to be necessary to complete an assertion. Strictly, however, any adjective or noun may, by attributing a quality or giving a name, make a complete assertion. > In the infancy of language there could have been no other means of asserting, as the verb is of comparatively late development> . [emphasis mine]

Is there any evidence for such a claim? Are there languages that function without verbs, or at least without a sophisticated verbal system? Or perhaps the earlier a language can be dated, the more primitive its verbal system and the less it relies upon verbs?

Since I’m not sure where I ought to go to answer this question (save perhaps some speculative universal history of language), I thought I should post it here. I welcome all thoughts, references, and jokes on the matter. (After all, verbum sapienti sat est.)

Regards,

David