http://screencast.com/t/OFuxlk7sWbZ
When there are two “u”s in a row, /u/ (high back rounded), the second on diphthongizes with the following vowel to create the sound /w (+ vowel)/ (voiced bilabial glide). For example, “uuestro” is pronounced /uwestɾo/.
The grapheme “ch”, /tʃ/ (voiceless alveo-palatal affricate) in Modern Spanish, was pronounced /ʃ/ (voiceless alveo-palatal fricative) in Old Spanish.
The c-cedilla, “ç” is pronounced as /s/ (voiceless alveolar fricative) as opposed to a hard /k/ (voiceless velar stop) sound.
In some cases, the “i” followed by “e”, such as in the word “uermeios” is pronounced as /ʒ/ (voiced alveo-palatal fricative), rather than the vowel /i/ (high front) before its transformation into the sound /x/ (voiceless velar fricative) in Modern Spanish.
The grapheme “y”, which is replaced almost always by the grapheme “i” in Modern Spanish, is pronounced as /i/ (high front). The pronunciation would be the same in Modern Spanish, but the grapheme “y” is used much less frequently now than the grapheme “i”.