However, Hebrew and its cognates were compared long beforehand, just
not necessarily
in such a systematic fashion. The thing is, anyone speaking multiple
Semitic languages,
and Hebrew speakers were acquainted with Aramaic already from the 7th
century BCE.
It probably started pragmatically naturally -- speakers realized that
many words were
similar across languages, so they'd use words from one language to
explain words from
ancient texts written in another that are less clearly understood. We
have various
examples of this from texts and persons attributed to the early
centuries CE, but
likely it started way beforehand during Biblical times.