The phrase "a sort of middle" is correct and usable in written English.
It can be used to describe something that is intermediate or not clearly defined, often in a comparative context.
Example: "The project is in a sort of middle phase, where we are still gathering data but have not yet reached a conclusion."
Alternatives: "a kind of midpoint" or "a type of intermediary".
"This is a sort of middle course they have adopted," he told the Dawn news channel.
Even now, at a sort of middle point, the confirmation process is still likely to be very loud and very mendacious.
Good examples seem to occupy a sort of middle ground between ambition and indifference, an unusual place to find an American wine.
I put on pants 50 years ago and declared a sort of middle road, Hepburn explained in 1981, with more candor than was typical of her.
Overusing words such as sensible and pragmatic, the commentariat insists that only a sort of middle England-friendly, marginal seat-focused compromise can walk into No 10.
Mary L. Schapiro, the chairwoman of the S.E.C., has not made clear what she wants to do, and members of the S.E.C. staff have suggested a sort of middle ground between the two alternatives that have seemed most likely.
The result is a sort of middle-class Lambrini: a sweet, cheap and rather bland wine that's fun to drink.
*also on protons inside an atom, but this is a sort of middle-scale and is a bit different from the small-scale strong force.
"It's a dark play about a man in his prime, who has money, position in society and all the women he can have, but he's now reflecting, in a sort of middle-life crisis, on what is really important in life," said Mr. Heng, who performs the monologue.
While many might see these options as a sort of middle-tier solution to the Rift and Vive, Microsoft expects VR running on the Xbox One X to compete on the high-end.
As Fox's sister, a sort of middle-aged adolescent (the opposite of the part she played on "Wonderfalls," a late, great show I am gratuitously calling back to your attention), Finneran keeps her dignity doing undignified things.
