diff --git a/markdown/design/subtitle-overlays.md b/markdown/design/subtitle-overlays.md
index 7adbe8a5ef..edcecd8e29 100644
--- a/markdown/design/subtitle-overlays.md
+++ b/markdown/design/subtitle-overlays.md
@@ -138,7 +138,7 @@ Multiple possible solutions come to mind:
     downstream with the overlay data, or one could attach the overlay
     data directly to the video buffers in some way.
     
-    Sending inline events has the advantage that is is fairly
+    Sending inline events has the advantage that is fairly
     transparent to any elements between the overlay element and the
     video sink: if an effects plugin creates a new video buffer for the
     output, nothing special needs to be done to maintain the subtitle
diff --git a/markdown/design/toc.md b/markdown/design/toc.md
index 38760377de..354beb104f 100644
--- a/markdown/design/toc.md
+++ b/markdown/design/toc.md
@@ -222,5 +222,5 @@ loops, …).
 
 API wise there is some overlap between: - exposing multiple audio/video
 tracks as pads or as ToC editions. For ToC editions, we have the
-TocSelect event. - exposing subtitles as a sparse stream or as as ToC
+TocSelect event. - exposing subtitles as a sparse stream or as ToC
 sequence of markers with labels
diff --git a/markdown/installing/building-from-source-using-cerbero.md b/markdown/installing/building-from-source-using-cerbero.md
index ff183de0d0..27863c4eae 100644
--- a/markdown/installing/building-from-source-using-cerbero.md
+++ b/markdown/installing/building-from-source-using-cerbero.md
@@ -193,9 +193,9 @@ GStreamer using the regular build process:
 
 Cerbero can be used to cross-compile GStreamer to other platforms like
 Android or Windows. You only need to use a configuration file that sets
-the target platform, but we also provide a set of of pre-defined
+the target platform, but we also provide a set of pre-defined
 configuration files for the supported platforms (you will find them in
-the `config` folder with the `.cbc` extension
+the `config` folder with the `.cbc` extension.
 
 #### Android