Hi JK, Iām still finding my voice and cannot say Iāve achieved a singing level that I feel good enough to make any of my covers public, but I want to share a little of my own experience and search.
I sing to acompany my guitar playing because is fun and convenient. Iāve found useful the concept that when a person plays the guitar and sings is playing two instruments at the same time, because it makes it clear that to play the guitar and sing well a person needs to work on each one as if he or she was learning to play guitar and saxofon at the same time.
The same way that a person could be ages learning to play guitar without significant progress, it could be ages learning to sing without significant progress, if the method is following, if any, is not geared the best to his or her needs.
The other concept that some have mentioned above is that speaking and singing are not as different as it looks. Sometimes that a person does not get the best sound out of his or her throat it may be because is forcing it go out in an unnatural way (assuming singing as we speak is the natural way). The risk of injury singing in a forced way is real and something to be aware of.
I think that being able to produce a specific pitch with the voice is something that can be learnt the same than other techniques. I thought until following the advice of Chris Liepe and checking my vocal notes with the tuner that my A2 note (fifth string) was good. It was not. It was more like a D3 in the Guitartuna App (this exercise works better with a chromatic tuner or a specialized app than with Guitartuna, but it was a good start). When I manage my throat to produce an A2 (it is very low for me), I cannot sustain it or do it consistently but I know that with proper lessons and practice time I should be able to achieve it.
As different guitars have different timbres each person has a different timbre in his or her voice. You should work to enhance yours rather than fight against it. Since my practice time is very limited I am working on my voice only marginally but it is something I want to work more in the future and the same way, I have to do it the way that works better for me.