balbuti

Another word the ancient world made out of a noise. Balb- is onomatopoeia: the Romans took the repeated syllable they heard, bal bal, and made an adjective of it. It is the same manufacturing process that produced barbaro at 2,135 out of bar bar, the sound a foreign language made to a Greek ear. Two words, both minted by imitating somebody else's speech, and both worth noticing precisely because of that: this is what it looks like when a language names people by how they sound to outsiders.

Which is why the register matters. Balbuti itself is neutral and descriptive, and it should stay that way. Say what is true - li balbutas, li havas balbutan parolon - and stop there. Do not perform the repetition in writing to make a character sound funny; it was a cheap joke in 1900 and it has not improved. The same rule this site applies on muta applies here: the word is for describing a person, not for doing an impression of one.

The second sense is ordinary and carries no weight at all. Most uses of balbuti in running text are about nerves, not about a speech difference: stammering out an apology, an excuse, a bad lie under questioning. Li balbutis ion pri la vetero is a person caught off guard, and nobody would read it as a comment on his speech. Balbutado is the stammering as a thing, and ekbalbuti is to start doing it - useful, because the interesting moment in a story is usually the one where the fluent character suddenly cannot get a word out.