Interesting question but look around a bit within Portuguese. Unlike Spanish, Portuguese is full of dialects that twist the standard language every which way. Even in Brazil, there is probably more phonetic diversity than in the whole Spanish-speaking world.
Look at <R-/-rr> as /rr/ vs. /h/
at /tio/ as /tiu/ vs. /c^iu/ , at <leite> as /leyti/ vs. /leyt/ vs. /leyc^i/ vs. /leyc^/
at <americana> as /@merikan@/ vs /@mErik@...@/
at my favorite <lã> as /l@~/ vs something like /lö~ö~/ a nasalized vowel somewhere between that US English foot and French feu
and so on.
My only experience in a Portuguese-speaking country was in Alentejo, where, except for the border, they spoke right out of the book. But I've met people from all over and the diversity amazes me. In grad school, was told that there's a different vowel system for every island of the Azores and a different dialect for every valley of N. Portugal.
But look at regional and social dialects in your own country. They're astounding.
From: Joao S. Lopes <josimo70@...>
To: Cybalist <cybalist@yahoogroups.com>
Sent: Tuesday, December 11, 2012 8:01 PM
Subject: [tied] The essence of sound shifts: a conceptual question.
Listers, forgive a humble laic friend, and let me ask just a conceptual doubt. What is the essence of a sound shift. I'll try to explain: let's suppose there 's a word <sak> in a hypothetical language, meaning "river". People say <sak>, everybody knows understand its meaning. Why will any person or group start to say, for example <sag> or <zag> or <sok>? I can understand situations when there's different strata. I understand that a French or a Portuguese will not pronnounce easily the English <th> or the German <ich>, but when there's not a contact between two layers of languages it's hard to understand shifts. It's also understandable that different synonyms substitute other ones, but not the shift of sounds. Is ther any hypothesis to explain the universal and continuous sound shifts around the world? Joao S.
Lopes