Creating custom articulation using regular text font

[Urs Liska]

I'm trying to create an articulation printing a glyph from the "regular" text font.

Copying from this (working) script definition list:

#(define asterisk-list
   `("asterisk"
      . ((stencil . ,ly:text-interface::print)
         (text . ,#{ \markup \musicglyph "pedal.*" #})
         ; any other properties
         (padding . 0.5)
         (avoid-slur . around)
         (direction . ,DOWN)
         (script-priority . 125)
         )))

I came up with the following:

#(define trill-list
   `("trill"
      . ((stencil . ,ly:text-interface::print)
         (text . ,#{ \markup "T" #})
         ; any other properties
         (padding . 0.5)
         (avoid-slur . around)
         (direction . ,DOWN)
         (script-priority . 75)
         )))

But when I integrate this and compile a file I get no output for the articulation and instead an error message, saying

programming error: Cannot get a text stencil from this font

I don't quite see why \markup "T" doesn't successfully create a stencil where in a comparable place \markup \musicglyph ... does.

Any suggestions what I could do about it?

Thanks Urs