Nerd alert! As many of you know, JRR Tolkien, author of 'The Hobbit' and 'Lord of the Rings,' was a historical linguist. I was just re-reading a bit of The Hobbit and noticed his linguistics coming out in his description of Bilbo's cold (caught riding those barrels down the river) at Laketown (near the end of the chapter 'A Warm Welcome'). He notes that for a time, Bilbo's public speeches were limited to "Thag you very buch." This happens when you're congested and have difficulty producing nasal consonants, which then revert to the homorganic non-nasal.
Or, as I tell my students, 'a cold in my nose' becomes 'a cold id by dose.'