First listen to how the impersonator of Jim pronounces the word "Hullo" as he greets Margaret:
In defence or clarification of his position Jack writes: "Now, when I’d lissend repeatedly to the first syllable of Hullo, I was cert·n that it ended with an ell. On the other hand I was equally sure that the second syllable began with an ell." In further support of his hypothesis, he looks at the tonetic structure of the phrase Hullo Margaret, which he characterises like this: "It’s a Fall-Rise tone and, as I’ve sed, its Fall element seems to me to include an ell. [...] Notice also that the word Margaret has not got a tone to itself but it’s incorporated into the tail of a rising tone."
Let's start with the tonetic structure.
I'd like to come back to Jack's auditory impression of two ells which he tries to substantiate by referring to "a separate further rhythmic pulse that clearly produces what we have surely to classify as an extra ell." If this "rhythmic pulse" is a purely auditory impression, I can't either verify nor falsify it because I can't settle in his brain. All I can do is demonstrate what I perceive as a long [l:] and a double [ll].
First, a version of what I perceive as a long ell:
Now a version of what I hear as two separate ells: