We consider approximation to two irrational numbers from a perspective of analysing the difference of their irrationality measure functions. It is well-known that this difference will change its sign infinitely many times. We continue the work of Dubickas and Moshchevitin, providing some new results on the distance between two irrationality measure functions. The main construction relies on the simultaneous analysis of denominators of convergents to two numbers, as well as some arguments from combinatorics on words. This is a joint work with Viktoria Rudykh.