Before
''de'' in spanish translates to of.
De donde = from where Possibly used in a sentence like "Where are you from?" = "De donde eres tú?"
Of which or of what.
"de vez", if that's spanish, means literally "of turn". It is usually used in the phrase "de vez en cuando", which means "every once in a while". Meaning "turn", "vez" can be used the same as in...