How do you refer to a specific great-grandparent? Does Chinese language has all 8 relationship titles to refer to one of them?
曾 is for paternal paternal ancestors, 曾外 for paternal maternal ancestors, 外曾 for maternal paternal ancestors, and 外曾外 for maternal maternal ancestors.
曾祖父, 曾祖母, 外曾祖父, and 外曾祖母 are only used in formal writings.
Paternal great-grandparents are 太爷爷/太奶奶.
(To help you memorize them, 爷爷 and 奶奶 are paternal grandparents.)
Maternal great-grandparents are 太姥爷/太姥姥 in the north and 太公公/太婆婆 in the south.
(姥爷/姥姥 and 公公（外公）/婆婆 （外婆）are maternal grandparents.)
I expect these terms to vary greatly in different regions and families. I was told to somehow call my maternal great-grandmother 太太, which also means "lady."