In front of z, s and x we have tz, ts and tx, their respective initial stop sibilants. BTW, word initial r's are not allowed in Basque. The j is pronounced different all over the country. The standard is like Yet, though a sound like Spanish Jota is popular in the heart of Euskal Herria, that is, Gipuzkoa and parts of Bizkaia and Nafarroa. And finishing now, vowels.
Basque vowels are simple.
The very last word, about stress. If the word is 4 syllables long, a secondary stress could appear in the last, specially is this is the -a marker.