Here is a quick background on some of your ancestors:
Indications are the progenitor of this SIAU family in this country was Louis SIAU of Languedoc France, a merchnt who settled in the Charleston SC area:
!SOUR 1825 GEORGETOWN DISTRICT TAX LIST
PRINCE GEORGE PARISH
SOUTH CAROLINA
SIAU, Lewis
1 Slave
!SOUR
http://www.genealogy.com/cgi-bin/ifa_image.cgi?IN=000757&...Genealogical Records: Early South Carolina Settlers
South Carolina Naturalizations, 1783-1850, Federal Records, Page 31
FEDERAL RECORDS
Name of Aliens AGE NATION RESIDENCE OCCUPATION ADMISSION
Siau, Louis 40 Languedoc, France Charleston Merchant 2 Jan 1817
John Ralph (born about 1743 Yorkshire, England - died 29 September 1801 Charleston, SC) and Ann --?-- were the parents of Tamson Ralph (born 13 Jun 1767 - died 7 Jan 1821 Georgetown, SC)
Tamson RALPH married 22 May 1784 in Charleston SC to John ADDISON (born 30 Sept 1757 - died 20 July 1804 George Town SC)
Children were:
1) John ADDISON (17 Aug 1785 - 20 Dec 1812) married Francis Ann Dunna... (page torn) 4 Dec 1811
2) ADDISON
3) Thomas Allston ADDISON (31 Dec 1787 - 4 Nov 1808)
4) Mary Richards ADDISON (29 DEC 1789 - 12 Oct 1812)
5) William Richards ADDISON (14 Sept 1792 - 9 Sept 1808)
6) Elizabeth ADDISON (15 May 1798 George Town, SC - 1 Oct 1877) married Francis L. SIAU
a) John Addison SIAU removed to Texas
b) Ann Eliza SIAU
C) Louis L. Siau
7) George W. ADDISON (George W. ADDISON was my ancestor) born 29 April 1801 Georgetown, SC - died 1 Dec 1852 Opelousas, St. Landry Parish, Louisiana.
Married 1) Martha Bell - Martha died shortly after the marriage..no children of this marriage.
Married 2) Arthemise RICHARD.
a) John Addison
b) Marie/Mary Temsey ADDISON
c) Eugene Isadore "E.I." ADDISON
d) Augustine ADDISON
e) Thomas Washington/Uhton ADDISON (my ancestor)