I have been thinking about this for a while. Given writing is essentially verbal speech transcribed into visual format, you would think that whoever is good at one should be good at the other. What do you think?
Depends, it's kinda like musicians and writing music. Being a skilled musician does not necessarily mean you can compose very well or write an awesome song. Sources: My father, he is an excellent musician, but has always envied those who can write music. He can read music just fine, and he's played in several bands, but he cannot write it.
I certainly don't think the reverse is true, that a bad speaker will be a bad writer.... I think being able to pick the right words in speech may definitely translate to being able to pick the right words in writing. But there's more to being a good speaker than just picking the right words, and there's more to being a a good writer than being able to pick the right words. So I'd say there may be a correlation in at least one area, but there's probably not anything close to a guarantee.
Piggybacking on what was said before me, I think that good speakers tend to have a strong voice and presence. Those things are very good to have in narrative, but how you achieve them in speech vs narrative is different. So, if a speaker has a strong voice and a unique presence, and that person understands how those things translate to written narrative, then sure, in this scenario, a good speaker could make a good writer. But, as BayView pointed out, there's a whole lot more to it. Maybe(?): "A good speaker who understands what's necessary to create a compelling spoken narrative has a strong base to become a writer if he or she understands the different applications of technique."
Or the opposite could be true too. That the frustrations bad speakers experience with verbal words fuels their desire (or necessity) to write because it's the only way they can communicate clearly. Stephen King said something similar to this about himself once, I think. And there's that little bit in Misery about the differences between storytellers and story-writers. Also, I've seem some interviews with authors that either couldn't speak worth a lick or were just nervous on camera. But then again some writers are very eloquent. There's probably no direct correlation between speakers and writers, but I can see how being either great or terrible could be a benefit in writing.
There's a huge disparity between how I write and how I speak. I can be very articulate in writing. But I speak very poorly. Lots of umms, whachamacallits, thingy, all ended in the all comprehensive closer "ya know?" When I'm typing or writing, proper diction just instinctively flows forth. But when I speak, I have all the vocab & eloquence of an eight year old. I think this disparity might be because I was actually full mute till I was 2 or 3 (so just a late bloomer, but my mom flipped out), and no one spoke great English around me—I was often left to the care of my Japanese grandmother whose Engrish is legendary. However, I was an avid reader and enjoyed Shakespeare at age 6 (which isn't all that impressive, when you're private elementary school required you to recite entire chapters of the King James Bible verbatim from memorization, regularly). So I think my speech & writing developed separately from each other
Speech is speed-based, really, isn't it? Your brain needs to go really fast to speak well, unless you're just reciting a prepared speech. Writing? Less so. Even without the benefits of rewriting, the simple physical act of writing things down (or typing them up) slows the presentation down. So people who think well but not as quickly will probably do better with writing.
I think that they share a subset of their related skills, but not a large enough subset that there's any assurance that being good at one will make one good at the other.
I'd agree with the rest that they're overlapping skill sets that don't guarantee proficiency in one just because you've got it in the other. I know my godfather was a great, charismatic speaker who couldn't write well to save his life, and I'm atrocious at talking (never mind publicly, just in general) but I like to think I get by all right when it comes to writing. @BayView definitely has a something about speaking having to with speed, and I'd also point out confidence. I don't think that "writing is essentially verbal speech transcribed into visual format" is really true. I definitely have different style in writing and in telling a story verbally, because in speech you have intonations and body language to add flavor, and you have to get that flavor differently in writing. Just trying to transcribe a conversation verbatim isn't going to make for good dialogue, for instance - that's why we have tags and beats and the like.
Completely agree with @ChickenFreak and @izzybot. You only have to read one lame book written by a great speaker, or hear one awkward speech or interview given by a great writer, to see that speaking and writing require some different skills. Learning how to do one more effectively should help anyone get a little better at the other, but there's way more to writing than just transcribing, and there's way more to speaking than just reciting.
I'm not sure if anyone's said this, but I read most of the comments and didn't see it. I think writing can also improve your speaking ability, it's improved mine. Writing dozens of different characters for years would definitely rub off, the longer you do it.
Actually I think writing has made me a worse speaker, lol. I'll launch into something and get stuck halfway, forgetting of course that I can't stop and edit in mid-speech.
^^ That's me. Even worse when I'm nervous. I'm not a terrible speaker but I wouldn't even compare it to my writing abilities. The same goes for English and my native language. I get stuck with both.
I don't think this. I think that many who are really good at oral communication are not skilled at written communication and the opposite, too. However, I think that this is also very much a matter of practise - I think that if you do have skills as a writer, you could probably practise and with time become a skilled speaker, too. But I don't think it's a given.
I don't think it is 100% correllated. Speaking and writing sound different unless the speaker is doing formal style speaking. Now it is feasible to dictate your thoughts and get them transcribed and then have an editor clean up the writing style. And while some folks can do both well, I doubt that it is a general rule.