diff --git a/extensions/workflows/sections/clause_9_input_output_fields_modifiers.adoc b/extensions/workflows/sections/clause_9_input_output_fields_modifiers.adoc
index 174875bf..e2f4e51c 100644
--- a/extensions/workflows/sections/clause_9_input_output_fields_modifiers.adoc
+++ b/extensions/workflows/sections/clause_9_input_output_fields_modifiers.adoc
@@ -1,9 +1,9 @@
 [[section_fields_modifiers]]
-== Input/Output Fields Modifers Conformance Classes
+== Input/Output Fields Modifiers Conformance Classes
 
-=== Requirement Class _Input Fields Modifers_
+=== Requirement Class _Input Fields Modifiers_
 
-The _Input Fields Modifers_ conformance class specifies how execution requests can modify
+The _Input Fields Modifiers_ conformance class specifies how execution requests can modify
 an input (including those specified using the _Collection Input_, _Remote Collections_, _Nested Processes_ and _Remote Processes_ conformance classes)
 by filtering its data according to its fields (properties), selecting a subset of the data fields or
 deriving new fields from existing ones (e.g., by performing arithmetic),
@@ -26,7 +26,7 @@ For an input generated by a nested process, this capability is equivalent to the
 _Output Fields Modifiers_ conformance class from the perspective of that nested process.
 For a remote process (as defined in _Remote Processes_ conformance class) that supports _Output Fields Modifiers_, or
 for a collection (or a process supporting _Collection Output_) with a data access mechanism providing the required functionality,
-it is preferrable to let the remote process or collection access handle the modification so as to lower bandwidth and processing requirements.
+it is preferable to let the remote process or collection access handle the modification to lower bandwidth and processing requirements.
 
 For an input from a _remote collection_, a data access mechanism for the collection may readily support some or all of these parameters (e.g., _OGC API - Features - Part 3: Filtering_).
 In this case, it is preferable for the Implementation to query the data with the relevant parameters.
@@ -47,9 +47,9 @@ include::../requirements/input-fields-modifiers/REQ_input-fields-modifiers_deriv
 
 include::../requirements/input-fields-modifiers/REQ_input-fields-modifiers_sorting.adoc[]
 
-=== Requirement Class _Output Fields Modifers_
+=== Requirement Class _Output Fields Modifiers_
 
-The _Output Fields Modifers_ conformance class specifies how execution requests can modify
+The _Output Fields Modifiers_ conformance class specifies how execution requests can modify
 the data output from a process by filtering its data according to its fields (properties), selecting a subset of the data fields or
 deriving new fields from existing ones (e.g., by performing arithmetic),
 and/or sorting the data according to the value of fields. An expression language such as the
@@ -74,7 +74,7 @@ When a nested process is used as an input to another process, this capability is
 _Input Fields Modifiers_ conformance class from the perspective of the parent process receiving the output of the nested process.
 For a remote process (as defined in _Remote Processes_ conformance class) that supports _Output Fields Modifiers_, or
 supports _Collection Output_ with a data access mechanism providing the required functionality,
-it is preferrable to let the remote process handle the modification so as to lower bandwidth and processing requirements.
+it is preferable to let the remote process handle the modification to lower bandwidth and processing requirements.
 
 The extent to which an implementation support these capabilities depends on its
 stated level of conformance to one or more expression language.