Ooooo! It's the goosonomia episoode! Yes, in the eleventh instalment of Glossonomia, Phil and Eric talk for a very long time (1:36) about the [u] vowel. In it, we talk about the evolution of the /u/ sound, and how historical /u/ turned into /aʊ/(as in "house"), while historical /oː/ turned into /u/ (as in "room").

We also discuss:

1. •goose fronting, especially in California, but also in South Africa
   

2. •yod, and its use in /ju/ and /jʊ/
   

3. •yod dropping after coronals, as in "tune, duke, nuke, Luke, suit"
   

4. •yod coalescence in accents like Cockney (/tju/ becomes [tʃu] for example)
   

5. •yod rhoticization in AAVE
   

6. •the "yew-hew" merger in places like NYC, Philly and Cork, Ireland
   

Articles referred to in our conversation:

1. •Changes in Progress in Canadian English: Yod Dropping
   

2. •A Majority Sound Change in a Minority Community: /u/ Fronting in Chicano English by Carmen Fought
   

3. •Socio-phonetics and social change: Deracialisation of the GOOSE vowel in South African English by Rajend Mesthrie
   

The Great Vowel Push Chain Shift, from J.C. Wells' Accents of English

Diagram showing how, when /o/ is fronting in RP, /ɔ/ rises and /u/ is fronted, also from Accents of English.