Talking with rhythm and emotion could be rapping, but not all rhythmic talking is rapping.
This, however, is about singing. The two primary factors for singing in tune and in doing “riffs” or embellishments, of being able to sing harmony, of being able to write melodic lines, are having a solid ability in hearing and singing intervals, be they scales, modes, or “melodic intervals”, such as in a song. If you cannot do pentatonic scales, then you cannot do “riffs”. You won’t hear them, you won’t emulate them, and you won’t be able to improvise, using them.
Melodic ear training and melodic exercises can quickly help to build the musicianship which modern music now demands. As a matter of fact, music has always made these demands, just the styles changed along the way.
Singing in tune requires excellent execution of melodic intervals, but wait, there’s more. Singing in tune also means that you, the singer, also can “interface” with your accompaniment accurately. This means that if you have a weak “harmonic ear”, you will hit notes sharp or flat, depending on your misperception of chords. Another factor of tending to sing flat, is having register transition issues which are ubiquitous among most singers who never took the time to get proper and effective vocal training.
Contrary to the misinformed, there are not several “methods” which “work”. There is technique which allows a singer to negotiate all the passaggi, and there is technique which does not. it doesn’t matter what the technique is called. It either works or it doesn’t.
I could not personally sing above chest voice until I got help. I couldn’t do it on my own. I didn’t know how and no matter what I did at that point, the “break” was there and I could only yell out high notes and go hoarse afterwards. So, even if your musicianship is superb, you still may need to handle register transition issues to have the freedom that an artist deserves.