Spanish words sound strange

[andresh29]

Hi, I'm using Alejandra-8khz america spanish voice and in general works fine, but i found some words that doesn't sound good.

e.g.: the word "miercoles" (wednesday)
I put it in my lexicon.txt:
miercoles 0 m i0 e1 r k o0 l e0 s

But the sound "ie" is a bit strange. It isn't pronunced clearly. Almost like the "i" is not pronounced.

The same happends with "aciertos".

In the americas spanish phoneme set (http://www.cepstral.com/es/tutorials/vi ... as-spanish) appears a phone "xi", used in many example words, but when I try swift, it gives me the message:

Unknown phone type in wrule "xi0" ignoring: miercoles 0 m xi0 e1 r k o0 l e0 s

Can you tell me what is happening, and how can i solve it?

Thank you very much!!!!

Andres