https://www.musical-u.com/learn/what-is-solfa-and-why-do-i-need-it/
Everyone can enjoy and benefit from singing. This form of music-making is the most basic instrument we can “play.” You can improve your singing experience with a powerful tool: Solfa. https://www.musical-u.com/learn/what-is-solfa-and-why-do-i-need-it/