Replace British spelling and fix various typos

tutorials/shading/advanced_postprocessing.rst

@@ -91,8 +91,8 @@ When displaying depth directly from the ``DEPTH_TEXTURE``, everything will look
 white unless it is very close. This is because the depth buffer stores objects closer
 to the camera using more bits than those further, so most of the detail in depth
 buffer is found close to the camera. In order to make the depth value align with world or 
-model coordinates, we need to linearise the value. When we apply the projection matrix to the 
-vertex position, the z value is made nonlinear, so to linearise it, we multiply it by the 
+model coordinates, we need to linearize the value. When we apply the projection matrix to the 
+vertex position, the z value is made nonlinear, so to linearize it, we multiply it by the 
 inverse of the projection matrix, which in Godot, is accessible with the variable 
 ``INV_PROJECTION_MATRIX``.
 

tutorials/shading/shading_reference/canvas_item_shader.rst

@@ -143,7 +143,7 @@ the texture color for such nodes, use:
 
   COLOR = texture(TEXTURE, UV);
 
-This differs from the behaviour of the built-in normal map. If a normal map is attached, Godot uses
+This differs from the behavior of the built-in normal map. If a normal map is attached, Godot uses
 it by default and assigns its value to the built-in ``NORMAL`` variable. If you are using a normal
 map meant for use in 3D, it will appear inverted. In order to use it in your shader, you must assign
 it to the ``NORMALMAP`` property. Godot will handle converting it for use in 2D and overwriting ``NORMAL``.

tutorials/shading/shading_reference/shading_language.rst

@@ -625,7 +625,7 @@ to shaders, Godot converts the type automatically. Below is a table of the corre
 +-----------------+-----------+
 
 .. note:: Be careful when setting shader uniforms from GDScript, no error will be thrown if the
-          type does not match. Your shader will just exhibit undefined behaviour.
+          type does not match. Your shader will just exhibit undefined behavior.
 
 Uniforms can also be assigned default values: