The reason "Edenics" isn't taken seriously is that it isn't, by scientific standards, serious.

To establish a kinship between two languages, linguists need to have whole series of words that can be traced to a common origin.

So, if we did not know Latin, we could reconstruct its lexic from French, Castillian, Catalan, Italian, Portuguese, Rumanian, etc.

For instance:

Here are the words for "horse" in those languages:

Portuguese: cavalo

Spanish: caballo

Italian: cavallo

Rumanian: cal

French: cheval

Catalan: cavall

From here, how can we find the Latin word for horse?

It seems that it should start with either "c" or "ch". But perhaps this is a coincidence? How can we know if it is not?

Because we have lots of words that begin with "c" in Italian, Portuguese, Castillian, Rumanian, etc., and with "ch" in French:

Portuguese - cabra, caminho, canção

French - chèvre, chemin, chanson

Which shows that there are regular transformations between French and Portuguese; some initial consonant in Latin morphed into "c" in Portuguese, Catalan, Italian, Rumanian, but into "ch" in French (and if we look at a map, we see that Portuguese and Rumanian are placed, respectively, at the Western and Eastern extremes of the geographical extension of Romance languages, so it isn't likely that the same innovation happened to both of them; it looks like the Latin consonant was preserved in both - and transformed in French.

The same reasoning helps us establishing that the first vowel of the Latin language should be an "a", not an "e". The second consonant is more difficult, because it went three different directions, morphing into "b" in Castillian, disappearing in Rumanian, and morphing into "v" in the remaining languages. But other considerations have led linguists to believe it was a "b" in Latin. And so on, so that we can reasonably guess that the Latin root for "horse" is something like "caball-".

We do know Latin, however, and we can see that the Latin word was "caballus" (OK; it wasn't; it was "equus" - which gave us the Portuguese, Castillian, Rumanian and Catalan word for "mare". "Caballus" was Vulgar Latin, and comes from the Classic word for "horse pack", which in turn is a borrowing from unknown origin).

Now compare this with the pair "direct"/"d-r-k". Which other English words correspond to a Hebrew (or other Semitic) root filled with "i" and "e"? Or, the other way round, which other English words, stripped from its vowels, correspond to a Semitic three-consonantal root? Do we find that "derelict", or "derailed", "deranged", "correct", "erect", "ferret", correspond to Semitic roots "d-r-k", "d-r-l", "d-r-g", "c-r-c", "r-c-t", "f-r-t", etc.? I do not know Hebrew, but I bet you that none of these happens, with the possible exception of "erect"/"eretz", where anyway the semantic relation is quite loose (upright vs great). And that is not random: it is a consequence of English and Hebrew not being related in any knowable way (they are possibly related, perhaps through a proto-language of both Proto-Indo-European and Proto-Afro-Asiatic - but we do not have the means, as things are, to reconstruct such proto-language). However, we do know the origin of the English words I listed above; they are borrowings from Latin or Old French; and the obvious relation between "direct" and "correct" can only be explained by the fact that "rect-" is a Latin root, and "di-" and "co-" are Latin prefixes. (If "direct" was related to "d-r-k", then "correct" is unexplainable, for in Semitic languages both words would be either unrelated or share the same three-consonant root - and then the English word for "correct" should be something like "daruct" or "deroct", which evidently isn't the case.)

In fewer words, bats are not related to nightingales, albeit the obvious fact that both can fly; on the contrary, nightingales are related to ostrichs, who don't. The flying is coincidental; the egg-laying vs breastfeeding is not.