[JasonFruit]

Its meaning is expressed by being spoken correctly, either in the imagination or out loud; as a poorly-specified representation of an expressive vocal sound, it's not meaningful in the same way that a real word would be. While it's not meaningless, it's certainly meaning-impoverished.

[littlekosh]

I’m curious as to your feelings on words such as bark, chirp, meow, splash, and mumble.

[JasonFruit]

I think you fail to grasp my meaning. The inflection of "uh" in that sentence is a greater part of its meaning than the pronunciation of the word, unlike the examples you gave. Onomatopoeia is a fine way to develop new words; inarticulate grunts that communicate hesitation in spoken conversation do not translate well to writing.