There are very few aspects of teaching that I don't enjoy. One of the ones I do enjoy immensely is just pronouncing words, preferrably multistress words, to model them for students: anXIety, eVENT, COMF'table. In my line of work, you can say them once, repeat them with exaggeration and drama. A single bugbear word can be several minutes of a lesson, first of all modelling the pronunciation with specific directions for tongue, tooth and lip locations; once mastering it, the student should next practice it in the context of a sentence, because producing a sentence takes some attention away from pronunciation - and pronunciation in real life has to be done with a lot of competing thoughts; and then they need to be monitoring themselves in speech to be aware if their accuracy has slipped. All of this entails a lot of repetition.
One of the recurring mysteries is how certain words can be so hard to say for some. ACcess, for one, is bothering one of my highly able students. He can say each syllable well, but together he either says: AXis or exCESS. When he stresses the first syllable, the vowel on the second automatically reduces; when he makes sure he says the correct vowel on the second, he instinctively stresses the second syllable, reducing the first. It does his mind in while I just get my kick from saying: ACcess, ACcess, ACcess.
There is also the mystery, constantly posed by another student, of how he is pronouncing what he is pronouncing. A common word like "that", he somehow mixes the "th" with "l" producing both sounds simultaneously. Usually mispronounced phonemes (sound units) are somewhere on a continuum of sound, like ten and -tain (from "maintain"). But there is virtually no continuum of sound between "th" and "l". I cannot replicate the sound (I may have once, but have no idea how I did it), yet he does it naturally when not monitoring the exact position of his tongue.
Of course, it's not always my students' pronunciation that can cause wonder; my own baffles me and others too. As stated in a blog sometime ago, my exuberant reading of difficult books in my youth caused me to create my own pronunciations for words I rarely heard. While teaching a few weeks back in the home of a friend, I defined a word my student, his wife, found: "AWry, that's when things don't go according to plan." The friend emerged from the kitchen cocking his head to one side to see this unfamilar word, before saying: aWRY. So much for the clouds of wonder that make an "infallible" teacher. "whilst" has also been mispronounced in a lesson by me.
Yesterday I borrowed a book I thought I must read: 100 words that everyone mispronounces. Here are the ones I have discovered that I fail at: niche, gnocchi, concupiscence, desultory, cadre, cache, lingerie, harass. (Of course, many of these have several "accepted" pronunciations which have to be considered correct.) While reading it though, I found one of my youthful pronunciations was in fact correct: BANal can have a first syllable stress!