From the website:
http://www.geocities.com/Heartland/Plains/9263/lang.html
I believe they are the same family and the page has lots of additional descendents.

Christian Lang b: Abt 1664 in Langen, Hesse, Germany
I haven’t confirmed this place of birth. The right city in Germany is difficult enough if you aren’t a native speaker. The wrong city is a nightmare.
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Misc. notes:
Married in PA:
Abraham (Lang) LONG BIRTH: 1743, Manheim Twp, Lancaster Co, PA USA
DEATH: ABT 1798, Warwick Twp, Lancaster Co, PA USA
Misc family notes
Father: John (Lang) LONG
Mother: Anna (John (Lang) Long) WIFE
Family 1: Maria (Abraham (Lang) Long) WIFE
MARRIAGE: 1746, Lancaster Co, PA USA
1.David (Lang) LONG