In particular, I’m after the placement of the stress or accent. Thus, is it
As tu RI as or As TU ri as?
Gal ee THI a or Gal EE thi a?
¡Muchos gracias!
Ga LI ci a. A STU ri as.
And it’s “Muchas gracias.” 
Does this mean that if a word ends with two vowel sounds (or a vowel sound followed by a vowel+“s”) the stress is placed on the third last syllable?
I’m not sure if there’s such a rigid rule.
As for the pronunciation of the c in Galicia, it’s only Spanish (Castilian historically) which pronounces *c *as th, not Galician or Catalan.
Words ending in “ia” and “io” are accented on the third to last syllable unless otherwise noted. There are several rules in Spanish concerning which syllable is accented when that I learned way back in high school Spanish. However, much like English grammar rules, those things have long drifted out of my brain.
as TU rias (it’s a dyptong, the i is weaker than the a, so a single syllable)
ga LI zia (same dyptong. The phonetic options for a written “c” are Z, S and K; if pronounced by someone from a seseo area it would be ga LI sia; the “ci” group is never a phonetic “ki”. The Spanish phonetic z is similar to one of the possible sounds for an English written “th”)
Words stressed in the last syllable are agudas: they only get a tilde if they end in vowel, n or s. ca-MIÓN.
Words stressed in the penultimate syllable are llanas: they get a tilde except if they end in vowel, n or s. Your two examples.
Words stressed in the third syllable from the end are esdrújulas; if even earlier, sobreesdrújulas. They always get a tilde. su per ca li fra gi LÍS ti co es pia li do so.
It isn’t just “such a rigid rule,” it’s about the first spelling rule you’re taught formally!
You mean accent, not tilde, right?
Well, I mean the little line on top. If that’s called an accent in the UK, then that’s it. I’ve met Americans who didn’t understand me when I said accent and I had to say tilde for them.
Y’all need to either agree on a single language or decide that it’s two different ones after all.
I would call it an accent, I’ve always though a tilde was that squiggly line that gives the letter N the little extra tonguey Y sound as in jalapeño.
Shrug, I’d never thought of the letter ñ as being “an n with an extra line” until I lived in the USA. An m is just “an n with an extra hump,” but for some reason nobody defines it like that. And the line on ñ is squigly or not depending on the letter type. I was taught a horizontal line, no squiggles; every typewriter I ever used which actually had an ñ had a horizontal line.
In any case, whatever you guys want to call it is fine by me so long as well all know that I’m talking about writing áéíóú and not aeiou, as a way to mark a stressed syllable when spelling rules demand it.
Websters:
For this reason, it always strikes me as odd when people (speaking in English) insist on pronouncing Barcelona as “Barthelona.” I can understand why you would use the “th” sound if you were talking about Barcelona in Castilian Spanish, but, when you’re speaking in English, it seems peculiar to impose a strongly Castilian pronunciation on a predominately Catalan city’s name.
Here’s the standard names for these things, according to the Unicode Consortium:
é is ‘Latin small letter e with acute’
è is ‘Latin small letter e with grave’
ñ is ‘Latin small letter n with tilde’
č is ‘Latin small letter c with caron’, which I only mention because it should be ‘Latin small letter c with hacek’ (originally háček) and nobody knows where the term ‘caron’ came from. (OK, we know it was used at Xerox when they designed fonts in the 1980s, but beyond that we don’t know.)
I don’t hear that very often, but I do hear Irish and British newscasters constantly refer to Valencia as “Valenthia”. That annoys me on a number of levels: because it’s the only Spanish name they ever attempt to give Spanish pronunciation to; because the Valenciano dialect (a subset of Catalan) doesn’t use the “th” sound; and because if they were giving it its proper Spanish pronunciation it would be closer to “Balenthia” anyway.
More completely and correctly that should be:
é is ‘Latin small letter e with acute accent mark’
è is ‘Latin small letter e with grave accent mark’
I’ve heard the “Valenthia” pronunciation, too, and it’s annoyed me for the same reasons that you cite. I’ve heard it (i.e., the Castilian “lisp” for Barcelona and Valencia) a lot in London, so much so that it seems to be the preferred pronunciation (or at least a very common one). I don’t hear it very often in the US, however, presumably due to the influence of Latin American Spanish.
Again in London, I would often hear people refer to “Sevilla” (with a “y”-sound for the double-l) instead of “Seville.” At least, in that instance, the pronunciation is very close to the local pronunciation.