(1) Please clarify, are we allowed expressing our dua (in our own language/words) after Dua-e-Mathura and before salam of salah? Whether the salah is fardh, sunnah, nawafil. Is this procedure correct and permissible?
It is not lawful to supplicate in one’s own language before turning salam whether it is fardh, sunnah or nafl salah. However one can supplicate in one’s language after turning salam.
Allah (Subhana Wa Ta’ala) knows Best
Darul Uloom Deoband