CoNLL-U Tree Browser/Editor

Readme

Use the file picker to load a CoNLL-U file (multiple sentences/trees are supported).
Use Prev/Next buttons or press < and > keys to navigate sentences. Pressing these keys will also save the current set of trees to an external file; if no such file is specified, the trees are dumped into the browser's local storage (use at your own risk!)
Edits in the textbox are automatically saved to the current tree when you navigate.
Use the “Hide/Show Editor” toggle to show or hide the editable tree textbox.
The table and analysis update automatically based on the current textbox content.
Press Shift+X to export your current trees as a .conllu file.

Keyboard Shortcuts

Navigation

< : Previous sentence
> : Next sentence
Ctrl+Shift+X : Export all trees to a .conllu file
? (shift /) : Toggle Help
K (shift K) : Add a comment to the textbox, indicating this tree was skipped for language reasons (e.g. Malay/Chinese sentence)
L (shift L) : Add a comment to the textbox, indicating this tree was skipped for lack of critical linguistic features (e.g. mojibake, list of phone numbers, ...)

Joining/splitting words (e.g. split ill to i 'll")

Be careful - these are difficult to undo!
Click on word 1, press + (shift =): This joins w1 with the next word w2. The resulting word inherits the properties of w1.
Click on word 2, press - (next to +). This joins w2 with the previous word w1. The resulting word inherits the properties of w2.
Click on word 1, press /. You will be prompted to enter at least two words. The resulting words inherit the properties of w1.

Changing part of speech

Click on a word.
Press N (noun, NOUN), V (verb, VERB), J (adjective, ADJ), A (adverb, ADV), D (discourse particle, INTJ), X (AUX), P (ADP, i.e. preposition), M (PROPN, i.e. name). (all are capitals, i.e. shift n, shift v, shift j, ...

ADV, ADJ, and INTJ are closely associated with the deprels "advmod", "amod", "discourse". Therefore, pressing A, J, and D will actually not only change the POS, but also the deprel, EXCEPT when the existing deprel is "root" (in this case, the POS will change but the deprel will stay as "root").

Changing root of a sentence

Changing a visible dependency's head or deprel

Click on the DEPREL label (the "pill").
1. Enter the values in the popup box, press "enter"/"Apply" to confirm; "escape"/"Cancel" to escape. OR
1a. Press Shift+left/right arrow to change its head.
1b. Press b (nsubj), o (obj), i (iobj), m (advmod), d (discourse), t (topic / "dislocated"), p (parataxis), c (ccomp), x (xcomp), a (advcl), l (acl:relcl), k (acl), v (vocative).

Adding a (visible) dependency (= changing a invisible dependency's head or deprel)