The human voice is the most versatile musical instrument ever discovered. No other instrument can perform lyrics! No other instrument can communicate through two languages: the language of music and the very language one speaks.
As in any human endeavour, the use of the human voice as a musical instrument is subject to standards. Its proper use, i.e. a high standard, can only be attributed to proper training and practice, be it self-imposed or through formal schooling and lessons.
Singing is one of the most satisfying performing arts. It is, to say the least, a truly addictive pursuit.