What is the difference between tartīl (recitation) of the the Qur’an and tajwīd (elocution) of it, and what is the relationship of madd (prolongation), tanwīn (nunation), and idghām (assimilation) to them?

"Tartil" (measured recitation) and "tajwid" (beautification of recitation) are close in meaning. Tartil is the measured and deliberate pace of recitation, while tajwid means to perform something well. In the terminology of reciters, tartil is one of the levels of tajwid, which are: tartil, tadwir (moderate pace), and hadr (fast pace). Reciting with tajwid encompasses these three levels. What is required religiously is that the Qur'an be recited with tajwid, using one of these levels. The rules of madd (prolongation), izhar (clear pronunciation), idgham (assimilation), and others are included within the rules of tajwid. Applying them in their proper places is required; some are obligatory, and some are permissible.