> The witness of the Targums and the LXX cannot
> be used to find the meaning of the Hebrew text.
>
Why do you say that? I would rather think the opposite since Hebrew was
still a spoken language at the time that the Targums and LXX were made
(although not by everybody), so I would assume that the translators had a
better understanding and knowledge of the language than what we can have
today. They might not have known the modern grammatical terms, but still
understood the meaning of the language. As far as the Masoretes and Karaites
are concerned, I would agree that their understanding might be more
influenced by other spoken languages of their time, since Hebrew was no
longer their native language, but only heard in synagogue.