In proper Spanish, the "Y" is prn. something an "ee" sound and a "J" sound. Not as harsh as a "J" sound. The English "J" sound is equivalent to a Spanish "Ll" (double L). As in the word "Llave"(key) . It is prn. JUH-veh. But when you say "yeso"(chalk), it is prn. ee-EH-soh. That is very proper Spanish, which is hardly used and varies from country to country. Like Ivayla pointed out, accents can be way different in every Spanish speaking country.
OK, ya no mas!, Hope that wasn't "demasiado", Magia.