But even with words, you're wrong. Just look at what you just typed. How many words in these sentences do you think are of latin origin?
That > Das
is > ist
What > was
I > ich
Said > gesagt (to say = sagen)
from > von
start > start
And so on and so forth.
It would be next to impossible for you to make a sentence in english that is mostly constructed on latin-based words. Yes, you can find many latin/french-based words in english. There were actually additions which in many many cases already had a germanic equivalent first, though.
It woud be even more obvious if you included the closer Dutch and especially Frisian examples.
Here's your list but instead of the German the Dutch words:
That > Dat
is > is
What > Wat
I > ik
Said > gezegd (to say = zeggen)
from > van
start > start
And some more examples:
Where > Waar
Here > Hier
See > Zie
Saw > Zag
Saw > Zaag (the tool)
Its a mess to conjugate in every language, from a semiotics point of view its because its one of the cornerstones of linguistic identity.
I'm still not sure its Germanic in origin in English though; ist is close to is, but so is est.
Ich is very different to I phonetically, and so is am from bin, and "I am" is a first priciple statement linguistically.
It is Germanic though: "From Middle English been (“to be”

, from Old English bēon (“to be, become”

, from Proto-Germanic *beuną (“to be, exist, come to be, become”

, from Proto-Indo-European *bʰew- (“to grow, become, come into being, appear”

. Cognate with West Frisian binne (“are”

, Dutch ben (“am”

, Low German bün ("am"), German bin (“am”

, Old English būan (“to live, wone”

. Irregular forms are inherited from the Old English verb wesan." -
http://en.wiktionary.org/wiki/be#Etymology
As for the closeness of est and is (the Dutch word is "is" too), don't forget that both the Germanic and Latin languages are themselves part of the far larger Indo-European language family.
Compare for example:
Mother > Moeder (Dutch) > Mutter (German) > Mater (Latin) > Mâdar (Persian) > Mā́tṛ (Sanskrit)
Father > Vader (Dutch) > Vater (German) > Pater (Latin) > Pedar (Persian) > Pitṛ (Sanskrit)