Does accepting ''  The principal parent of Yiddish is High German, the form of German encountered by Jewish settlers from northern France in the eleventh century.' as true logically compel one to accept 'There is a principal parent of Yiddish which is High German.'
'  The principal parent of Yiddish is High German, the form of German encountered by Jewish settlers from northern France in the eleventh century.###There is a principal parent of Yiddish which is High German.