This is a modification of Tengwar Sindarin by Daniel Smith that includes a transcriber for Classical Mode, built on OpenType substitutions. Just apply the font to any Quenya text and observe the magic:

Everything should work fine, but I haven’t tested it extensively, so bug reports are welcome!

• S is always denoted by silme, since there’s no way for a font to understand etymology. If you want súle instead, you have to spell out TH.
• Noldo is not used anywhere by default, for the reason above and because no Classical Mode samples of it are known. Type Ñ if you want it anyway.
• To denote duodecimal 10 and 11, J and Z are used, since they’re the only Latin letters that never appear in transcriptions of Noldorin Quenya.

• Test & fix stuff
• Use appropriate feature tags, not just liga
• Replace some substitutions with positioning
  • S-hook + tehta
  • Tengwa + tehta (no separate glyphs)
  • Diphtongs?
• Simplify stuff
  • Lookup flags: lookupFlag IgnoreMarks; sub ...
  • Chaining substitutions: sub @classA @classB' lookup LookupName;
  • Consider renaming basic consonant glyphs to [a-z]
• Combine glyphs for long vowels & diphtongs to simplify GSUB? (Learn hinting)
• Import issues (tables reference)
  • Ignoring 'PCLT' PCL 5 data table
  • Windows will reject fonts with an OS/2 version number of 0
• Export issues
  • Em size should be 1000, not 2048 for OpenType (not an error though)
  • Self-intersecting eleven
  • Missing BlueValues entry
• Double-stroked capital letters (version 2.0)

• Ligatures (many-to-one)
  • liga — default
  • rlig — required
  • clig — contextual
• Contextual alternates (one-to-one)
  • calt — default
  • rclt — required
• (De)composition: ccmp
  • One-to-many
  • Many-to-one
• Position
  • kern — default
  • dist — required (does it work for Latin?)
  • mark — marks (tehtar)
  • mkmk — mark-to-mark (Y + vowels?)

pos @classA <left bottom extraWidth extraHeight> @classB <left bottom extraWidth extraHeight>;
pos A B marginBetween;

I plan to add double-stroked capital letters, but there are two problems:

• It’s not trivial to copy glyphs to another font with hinting (and other similar data?) preserved
• None of the original four typefaces have tehtar for capital letters (they need to be slightly bigger and higher)

To solve the first issue, I could just use a separate fallback font, but if anyone knows how to do it properly, please let me know. Or if you’re willing to create the tehtar variations (I’m not an actual type designer).