Top 10 Instruments Very Difficult/Impossible to Sing With
Not all of these instruments are easy to sing with. Some of these are very difficult. And some of these are also impossible.There are singers who sing and play drums at the same time. But I have seen most of them usually play snare and ride while singing. But when they don't sing they goes for more. Plus playing snare and ride is also difficult. Cause it requires physical strength.
Its fretless. While you can measure the notes in guitar with frets. But its very hard to measure the notes without frets. Plus singing. Very hard.
I have uploaded an image of tapping. Though tapping isn't only for lead guitar. But usually it can be found in lead guitar (solos). And its pretty common to see even good guitarists look at their guitar when tapping, so they barely could sing at that time (tapping just of an example).
Yes, it's very hard to sing lyrics and play guitar at the same time. Sometimes you end up just making up lyrics which sound like what sound the guitar is making. I'm sure Stevie Ray Vaughan and the others zxm mentioned found it very difficult too.
David Gilmour, Kurt Cobain, Jimi Hendrix played lead guitar and sang at the same time. But its much more difficult than rhythm guitar. Lead guitar requires have more notes and more techniques.
Not only one keyboard. I meant more than one keyboard.