Adrian began by pointing out how central pronunciation is to language learning. And while this is obviously true for spoken production, it is also true, surprisingly enough, for reading, writing, or even thinking in the target language. For example, during reading, we tend to sub-vocalize, that is, hear the words aloud in our heads. And how will these words be pronounced in our heads? In the default, which will often be our L1. So you can unwittingly reinforce that default every time you read. Adrian pointed out, with the example of his own experiences of French at school, the lamentable effect of persistently awkward pronunciation on motivation to learn a language.
Adrian's talk then took a problem-solution structure with two problems. First, pronunciation is often presented as an endless open set, with no syllabus against which to fix a sense of progress. Second, it is often presented cognitively, where it needs to be presented bodily. The solution to problem 1 was to present a complete set of sounds as a single system, and here, Adrian introduced us to his famous phonemic chart. The solution to problem 2 was to go beyond mere repetition and make students aware of the muscular and bodily feel of the sounds. Here, Adrian mentioned the four 'buttons': tongue, lips, jaw and voice.
Adrian strongly recommended integrating pronunciation from day 1, and in all stages of teaching. He made the point that we can't 'retrofit' pronunciation, that is, teach the words and grammar first and then return later to tinker with the pronunciation - by then it will be too late. What's more, we have to teach the sound system as a whole. An individual sound or contrast only makes sense when placed within a framework.
Perhaps the most interesting observation, for me, was when Adrian pointed out that each square in his chart represents an area, rather than a precise phonetic realization. In this way, his chart is flexible enough to use with varying allophones and consequently, accents.