diff --git a/ocrd_calamari/recognize.py b/ocrd_calamari/recognize.py
index 772c680..0624d9b 100644
--- a/ocrd_calamari/recognize.py
+++ b/ocrd_calamari/recognize.py
@@ -100,6 +100,11 @@ class CalamariRecognize(Processor):
                     line.set_TextEquiv([TextEquivType(Unicode=line_text, conf=line_conf)])
 
                     # Save word results
+                    #
+                    # Calamari OCR does not provide word positions, so we infer word positions from a. Unicode text
+                    # segmentation and b. the glyph positions. This is necessary because the PAGE XML format enforces
+                    # a strict hierarchy of lines > words > glyphs.
+
                     def unwanted(c):
                         return c == " "