Connotations

"Hmmm....." It's jolly difficult you know, to read expression in the written word. I mean, take that Hmmm which the Deputy Head so kindly left. Could it be taken as a murmur of approval, shorthand say for "Goodness gracious, I didn't know the dear girl had been paying attention so intently in class, and to apply herself to work outside the classroom so energetically, well, I am gratified...." or " What a clever pupil, and how gratifying that she should use me as the role model....."
(New paragraph)It's not easy you see unless you can hear the tone of voice that was used. Emphasis is the word I think our erstwhile Head of English, one E.ver P.resent (well he's always hovering nearby when mischief is afoot) Armstrong, would use. You can follow the reasoning in the sentence, "the cat sat on the mat", as in "the CAT sat on the mat", "the cat sat on the MAT", or "the cat SAT on the mat."..... three different emphases..
So back to ol Postie and his Hmmmm...... There is of course a third option, the hmmm forced through gritted teeth, the raising of the eyebrows, the scowl, the fingers twitching as if holding an imaginary cane. Knowing my station in life, as a lowly pupil at private school, I reluctantly admit I rather favour the latter.... The choice that is, not the consequences. I don't want to be on the carpet again, it's starting to wear a bit thin where my feet shuffle about, explaining myself to an irate Beak, but in an unfair world I think the last line of the poem will come to fruition, and Sir will doom me to Detention.