When and how shall tones be taught in Chinese learning?

Chinese is one of the tonal languages. It has 4 syllabo-morphemic contour tones. Many CSL learners and teachers take tones as the most difficult part in mastering pronunciation. Traditionally, teachers tend to emphasize the initial-final-tone or vowel-consonant-tone orders in teaching. However, in my opinion, tones should be clearly and fully taught from the very beginning. In brief, I call it “Tones First”. After explicitly describing the foundational reasons, I will put forth what should be basically considered for enacting the TF principle. In short, the following factors must be taken into consideration: (1) the common segmental units that both L1 and L2 have; (2) tone combinations; (3) the interaction of tone and intonation; (4) the interaction of tone and stress. Reasonable arrangement or design will make teaching and learning more effective. Some examples are given in this article.