diff --git a/text/v2/gotext.go b/text/v2/gotext.go
index 9cdb7361b..e10add466 100644
--- a/text/v2/gotext.go
+++ b/text/v2/gotext.go
@@ -36,6 +36,10 @@ var _ Face = (*GoTextFace)(nil)
 // GoTextFace is a Face implementation for go-text's font.Face (github.com/go-text/typesetting).
 // With a GoTextFace, shaping.HarfBuzzShaper is always used as a shaper internally.
 // GoTextFace includes the source and various options.
+//
+// Unlike GoXFace, one GoTextFace instance doesn't have its own glyph image cache.
+// Instead, a GoTextFaceSource has a glyph image cache.
+// You can casually create multiple GoTextFace instances from the same GoTextFaceSource.
 type GoTextFace struct {
 	// Source is the font face source.
 	Source *GoTextFaceSource
diff --git a/text/v2/gox.go b/text/v2/gox.go
index 98cec7d9d..625215d82 100644
--- a/text/v2/gox.go
+++ b/text/v2/gox.go
@@ -37,6 +37,9 @@ type goXFaceGlyphImageCacheKey struct {
 // GoXFace is a Face implementation for a semi-standard font.Face (golang.org/x/image/font).
 // GoXFace is useful to transit from existing codebase with text v1, or to use some bitmap fonts defined as font.Face.
 // GoXFace must not be copied by value.
+//
+// Unlike GoFontFace, one GoXFace instance has its own glyph image cache.
+// You should reuse the same GoXFace instance as much as possible.
 type GoXFace struct {
 	f *faceWithCache