Scientific studies have demonstrated repetition is one of the ways we retain information.
Repeating a sound helps learners correct their pronunciation. Permanent storage into the brain’s neural pathways requires practicing word pronunciation in 5 to 12 repetitions over time.
Practicing pronunciation over days and weeks naturally forces the sounds into the subconscious and permanent storage for regular use.
As skills improve, consciously thinking about English pronunciation is no longer necessary. Practice over multiple days each week and at least three months.
Equally important is your concentration on hearing sounds within each word and attentively reproducing the sounds you hear. Perfect pitch is a rare ability of a person to hear and identify sounds, 1 in 10,000 people have perfect pitch. Some learners are better at hearing sounds than others. Improving your ability to hear sound variations requires practice. Some will require more practice than others; some might need a voice coach to assist them.
Listening carefully to the sound variations within words and sentences and noticing the variations and aspects of how they are produced is critical.
You must also hear the sounds you yourself are producing and compare them with the word sounds you hear. If you cannot identify the differences between the sounds you hear, and the sounds you speak, these exercises could be counterproductive as you will improperly train yourself with the wrong pronunciations. I suggest you employ the services of a voice coach to improve your hearing and reproduction and then use these workshops as reinforcement practice.