Linguistic Tree Constructor (LTC) is a tool for drawing lingusitic syntax trees of already-existing text.
It is a syntax editor, not a text editor, so the text has to exist already. It is best suited for large-scale, rapid creation of hand-annotated treebanks.
The user can define their own node categories, and can label each node with labels, also definable by the user. LTC supports "generic", X-Bar and RRG trees.
Supports interlinear texts in SIL SFM format.