The phoneme /w/ [a voiced labio-velar approximant, lip rounding] has multiple and productive sounds in the spanglish and espanglish Xicano community.
For us there are choices to be made between:
Gíüey, huey and wey
Gíüero, huero and wero
What, guat and huat
Wacatelas, guacatelas and huacatelas (seldom seen written as thus)
Wacha
Wayno (although to english this is better represented by why-no)
Wachatelas
Wuacara, guacara
Wacha (watch) (notice the eliptic u [it sounds as guacha]once it is pronunced in espanglish)
The fact is that this phoneme has various representations when it comes to the written spanglish/espanglish Xikano language.
However, there is a clear distinction once it is blurted out of ones mouth.
I particularly noticed this in my trip to Mexico City. They had a curios expression going on there. More than several times I noticed that people responded with a what? when addressed, although their what sounded more like a guat with a /g/ (clear and distinct velar stop), and were, for the most part, unable to render a clear and pure /hw/.
The curios thing about this phenomenon is that it would seem to appear that it is stricly a border phenomena.
Note: Especially in AmE and Scots, there exists two allophones of /w/ that actually become separate phonemes, /w/ and /hw/. The /hw/ is a voiceless labiovelar approximant, like a /w/ with a puff of air (an /h/) to start it off. It normally is spelled with [wh-], as in [what, where, whistle, whoop]. It is becoming increasingly rare in EngE and has no major significance in AmE, some people using it and others not.
Note: Like /j/, /w/ is a semivowel; they are proniunced like vowels, but function like consonants. (notes: David Minugh, Stockholm University)
The point here is that there is a semi-vowel shift going on just now in the border towns, which makes for a pretty interesting thang, so yeah, that.