According to
http://www.script-o-rama.com/movie_scripts/f/forbidden-planet-script-transcript-leslie.html (not a perfect transcript, but I couldn't readily find a better one), the word "philologist" occurs in two scenes. The first is when Morbius makes radio contact, and the second is right after lunch at his estate.
In the second scene, Adams explains a philologist to be "an expert in words and languages." In-universe, defining the term out loud underscores his point that Morbius appears to lack the qualifications to build Robby. But also, no doubt a secondary function of the dialog is to explain to the audience what a "philologist" is.
As for the first scene, it is Doc Ostrow who utters the line "Philologist?", not Adams, and rather than conveying curiosity, I read the delivery as conveying Doc being impressed, as in
Gee, they thought of everything.
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On the issue of whether the Krell machine radar-scanned the
Bellerophon when it first approached, here are some further thoughts and questions.
First, it's pretty clear that Altair IV had been surveyed before the
Bellerophon expedition, because the crew was checking the continents against the "old charts" on first approach, and Morbius asks Adams to refer to "standard charts" when dictating the landing coordinates. If the
Bellerophon was radar-scanned when it first approached, then I doubt that the survey which made the old charts got very close to the planet, or else it should have been radar-scanned too and the C57-D crew would have known to expect this. On the other hand, if the
Bellerophon were not radar-scanned, then that removes any such constraints on the trajectories of earlier survey craft.
Second, immediately after the radar scan is when Morbius calls the ship, and he makes reference to the ship being tracked. Now, this could be Morbius interpreting the operation of the machine as preset by the Krell. Indeed, later he makes reference to the fact that the machine registered the approach of the ship from deep space, perhaps even well before the radar scan. Or, on the other hand, did Morbius figure out how to trigger a radar scan from the Krell machine, to scan an object the machine had already detected approaching from deep space?
Third, Morbius speaks of a minor alteration performed throughout the machine "years ago." What was the alteration, why does he think it was performed, and when did it supposedly occur? I've always assumed that it was his use of the machine that triggered the alteration, and that the alteration was the instantiation of the mechanism to objectify his desires, including that for seclusion. Could such an alteration include watching deep space for approaching Earth ships? Or, is the deep space detecting process just a function of the machine as intended by the Krell, and an extension of the mechanism that registers birds and deer?